Good News for Yo-Yo Dieters!

[PB Girl]

I found this in Shape Magazine, Sept 2003:

There's little scientific evidence that ultralow-calorie diets and yo-yo dieting do any permanent, long-term damage to your metabolism, or affect body-fat distribution, says Susan Roberts, PhD., professor of nutrition at Tufts University in Boston. "Granted, metabolism slows a bit when you lose weight, but that's because you also lose a little of the muscle that helped support the extra fat," she adds. "Drop a few pounds of muscle and your metabolism slows by about 9 calories for every pound of muscle lost." The biggest reason not to follow a very low-calorie diet is that it will rob you of essential nutrients. Also, such a diet can lead to bingeing on high-calorie fare, which results in weight gain, not loss.

I think this is great news! Most of us probably have dieted in the past with Low Fat or reduced calorie. I thought that some of you would enjoy reading this! :)

[Lisa N]

Does this article give references to any studies that back up what she says? It's one thing to say it theoretically, but quite another to prove that yo-yo dieting and calorie restriction have no long-term impact on metabolism.
For example, Ms. Roberts states that metabolism slows roughly 9 calories for each pound of muscle lost, but a pound of muscle burns between 25 and 50 calories daily. What compensates for the rest?
It would be wonderful if what this article states is really fact, but it would seem that the actual experience of many here shows otherwise.

[ItsTheWooo]

Does this article give references to any studies that back up what she says? It's one thing to say it theoretically, but quite another to prove that yo-yo dieting and calorie restriction have no long-term impact on metabolism.
For example, Ms. Roberts states that metabolism slows roughly 9 calories for each pound of muscle lost, but a pound of muscle burns between 25 and 50 calories daily. What compensates for the rest?
It would be wonderful if what this article states is really fact, but it would seem that the actual experience of many here shows otherwise.

Out of curiosity, not to offend anyone, but I've never seen someone claim to have a slow metabolism from yo-yo dieting that also wasn't eating a lot, going "off their diet plan" often, developed emotoinal eating problems (from years of dieting) and aged physically many years (increasing IR/slow metabolism) since they last remember being thin.
Or in other words, it might be the yo-yoing. Or it might be the things that yo-yoing encourages that are doing it. A history of weight cycling correlates with poor self image/dysfunctional & unnatural food intake patterns (which could contribute to higher weight). It also correlates with fad dieting (which could contribute to increasing insulin resistance from trying diet trends that are unhealthy... as well as rebound junk food eating). Obviously, a history of yo-yo means you are relatively older than you were when last thin. The metabolism of a young person is relatively higher than that of an old person; old people need less energy than young people because they tend to be less active and their bodies don't use energy & regenerate tissue like the young.


Speaking personally: I think my metabolism is pretty normal and I"ve lost considerable weight over a long period of time. Assuming I control carbs, it gains and loses at appropriate intakes relative to weight & activity (and diet too). I more easily gain than someone naturally this weight, but then again this weight is on the low end of normal for me so that makes sense. I think if I were more like 125-150 pounds (which is more comfortable for my bod) I wouldn't have that issue.

[kwikdriver]

Does this article give references to any studies that back up what she says? It's one thing to say it theoretically, but quite another to prove that yo-yo dieting and calorie restriction have no long-term impact on metabolism.



How can she reference these articles when her position is that they don't exist? It's also impossible to prove a negative -- but it should be easily possible to prove a positive in this case. Where's the research showing that yo-yo dieting does, or even can (sometimes does) permanently harm metabolism?

[Lisa N]

How can she reference these articles when her position is that they don't exist?

I read the article again, but I don't see it. Where does Dr. Roberts claim that studies on the effects of low calorie dieting on metabolism don't exist? She may claim that the effects don't exist, but on what is this claim based?
True, you can't prove a negative, but you can certainly study the effects (short and long term) of very low calorie and yo-yo dieting. I've searched and cannot find a single long-term study on the effects of very low calorie dieting (the longest I found was about 16 weeks). Also, if no long-term studies exist, how can she make the claims that she does; long term there is no effect? On what is that statement based, then?
What studies have been done show that the typical low calorie dieter loses a lot of muscle mass due to inadequte protein thereby slowing metabolism. After the dieter stops, they go back to their previous intake, but with less muscle mass begin gaining more rapidly. Each successive time the cycle repeats, more muscle mass is lost and metabolism slows accordingly. Ever hear of the term 'skinny fat'? Those in that category are within a normal weight range, but have a higher body fat percentage than expected due to the loss of lean body mass.
I see no reason to scoff or accuse people of being unaware of their caloric intake when they claim that yo-yoing messed up their metabolism...it's quite likely, in fact, that they are telling the truth.
Other studies have shown that very low calorie dieters have a high incidence of gallstones (of which about 30% will require surgery).

[K Walt]

Closest I know of are listed at the end of this article.

http://www.techcentralstation.com/113004E.html

[PB Girl]

Ms. Roberts states that metabolism slows roughly 9 calories for each pound of muscle lost, but a pound of muscle burns between 25 and 50 calories daily. What compensates for the rest?

I noticed this too and wondered about the remaining calories.

I know that this excerpt created a lot of controversy on here, but it is a rather limited quote from a magazine. We would have to research the university's studies to find the proof for her statements.

[kwikdriver]

I read the article again, but I don't see it. Where does Dr. Roberts claim that studies on the effects of low calorie dieting on metabolism don't exist? She may claim that the effects don't exist, but on what is this claim based?


From the first sentence of the article:

There's little scientific evidence that ultralow-calorie diets and yo-yo dieting do any permanent, long-term damage to your metabolism, or affect body-fat distribution, says Susan Roberts, PhD., professor of nutrition at Tufts University in Boston.

[kmct10]

Maybe your metabolism slows down on low-cal from starvation, but on low-carb it certainly feels like it speeds up, and I'm stuffing myself. Or perhaps it slows down in the sense that your heart does not have to work so hard to pump blood to all the fat, and the pancreas and liver to pump out insulin and process glucose/glycogen. This shows what people have been suffering with needlessly.

[Lisa N]

From the first sentence of the article:

Ahhh..but little does not equate to none. ;) Keep in mind the wholesale writing off of low carb by the 'experts' as damaging to kidneys (too much protein), bones (leaches out the calcium, you know), heart disease (all that fat is a sure recipe for a heart attack!), etc...all with claims of sound scientific backing by those making the claims.
The fact is that we have no long term studies (over a period of several years) showing that what she claims is, indeed, fact and what studies do exist don't seem to support her view. Even the Ancel Keys study mentioned above showed that 3 months after dieting ended, the majority of the participants had regained their lost weight plus 10% (much of which was fat, not muscle) and even this does not show the true effect of repeating the process over and over because it was only once.

[kwikdriver]

The fact is that we have no long term studies (over a period of several years) showing that what she claims is, indeed, fact and what studies do exist don't seem to support her view.

Which studies are these? I've never seen any. Don't see any here, either.

Even the Ancel Keys study mentioned above showed that 3 months after dieting ended, the majority of the participants had regained their lost weight plus 10% (much of which was fat, not muscle) and even this does not show the true effect of repeating the process over and over because it was only once.

The relevant Keys quotation follows:


Three months after the dieting, though, none of the men had regained his former physical capacity, noted Keys. On average, the men regained to their original weights plus 10%. But the weight regain was largely as fat and their lean body mass recovered much more slowly.

So they lost lean mass and their metabolism slowed as a result -- which is something Roberts said happens above, and which just about anyone with a smattering of knowledge of nutrition already knows. Everyone also knows that 95% of dieters gain the weight back plus more -- but that doesn't mean it's the result of some kind of damage they've done to their metabolisms. The Keys thing is next to worthless, and qualifies as what I would call "little evidence." It's better than no evidence at all, but not much.

Keep in mind the wholesale writing off of low carb by the 'experts' as damaging to kidneys (too much protein), bones (leaches out the calcium, you know), heart disease (all that fat is a sure recipe for a heart attack!), etc...all with claims of sound scientific backing by those making the claims.

And when people talk about stuff like this, they are referring to scientific evidence that doesn't exist. Roberts is also doing that -- from a different angle. She's saying it doesn't exist in the first place, and basing her conclusions on that. In fact, the people who claim this "metabolic damage" happens are doing what the anti-low carbers are doing: claiming the existence of something despite the lack of clearly supporting scientific evidence.

[nobimbo]

There is some very interesting results that came out of a Minnesota study on the effects of semi-starvation that David Garner wrote about in a book about eating disorders. The men in the study did have lower BMR's during the study, and their BMR's increased once they began eating again. They gained on average all the weight they lost plus 10%, but eventually lost that extra weight. The most interesting aspects of the study were the psychological changes that the men experienced during semi-starvation and during the follow-up period, including obsessive thoughts about food and binge eating. A yo-yo dieter who keeps trying to lose weight on very low calorie diets is most likely doomed to a lifetime of irrational thoughts about food, leading to repeated rebounds in weight.

Here is a link to the article:

http://www.possibility.com/epowiki/Wiki.jsp?page=EffectsOfSemiStarvation

Linda

Editing this to add that I just realized this info was already posted; I can't figure out how to delete this, sorry! I should have read all the posts in this thread first.

[Samuel]

Three months after the dieting, though, none of the men had regained his former physical capacity, noted Keys. On average, the men regained to their original weights plus 10%. But the weight regain was largely as fat and their lean body mass recovered much more slowly.


So they lost lean mass and their metabolism slowed as a result -- which is something Roberts said happens above, and which just about anyone with a smattering of knowledge of nutrition already knows. Everyone also knows that 95% of dieters gain the weight back plus more -- but that doesn't mean it's the result of some kind of damage they've done to their metabolisms. The Keys thing is next to worthless, and qualifies as what I would call "little evidence." It's better than no evidence at all, but not much.



Keep in mind the wholesale writing off of low carb by the 'experts' as damaging to kidneys (too much protein), bones (leaches out the calcium, you know), heart disease (all that fat is a sure recipe for a heart attack!), etc...all with claims of sound scientific backing by those making the claims.


And when people talk about stuff like this, they are referring to scientific evidence that doesn't exist. Roberts is also doing that -- from a different angle. She's saying it doesn't exist in the first place, and basing her conclusions on that. In fact, the people who claim this "metabolic damage" happens are doing what the anti-low carbers are doing: claiming the existence of something despite the lack of clearly supporting scientific evidence

I always prefer logic over medical explanation. Low calorie dieting makes use of a feature which the human body have developed over millions of years. This feature allows us to store energy when food is plentiful to use back when food is short.

So I agree that low calorie diets cannot harm us since our bodies are made to handle them. However after the diet is over, our bodies don't only gain back all the weight lost + 10%, they try to maintain the new larger weight forever. To some people this means metabolic damage.

Now why should we gain more than we lose during the diet? I think our bodies apply the same logic they apply with vaccination. After defeating the weak virus our bodies get through vaccination, they strengthen our immunity against this particular type of virus so we become able to defeat a stronger one. Applying the same logic, after each low calorie diet, our bodies decide to make us able to stand a more severe food shortage period by increasing our body fat.

[VALEWIS]

Just wanted to comment that body builders are always doing bulking and cutting cycles. They are very knowledgable about what is called nutrition partitioning. If you eat sufficient protein while eating very low calorie, lean mass is mostly spared and fat is lost.
When you just eat very low calorie everything as in starvation, more muscle is lost. Body builders are able to lose fat over and over in the process of bulking and dieting without it permanently affecting their metabolisms. Weight loss dieting does cause metabolism to slow during the dieting period, but never more than 35%, as shown in the the many starvation studies, but things return to normal.
The notion of yo-yo dieting affecting metabolism permanently is an unproven theory. If you live long enough and continue to diet off and on, then yes, but it more likely due to normal ageing slow down not to diet history.

[Samuel]

Both muscles and fat can be used as energy reserve. So when someone loses fat and gains muscles at the same time, his body could see no reason to restre his fat back.

[Nancy LC]

There was another article posted awhile back essentially saying the same thing.

http://forums.lowcarber.org/showthread.php?t=250433&highlight=metabolism

I did some research into how many calories a pound of muscle burns. First thing I run into are some of the non-medical bodybuilding sites claiming something like 30 calories a day (I think it was day). Then I started using scholar.google.com to search and found more credible sources saying something like 2-6 calories more than fat. Yes, fat does burn a small amount of calories, it isn't totally inert like we've been told.

[Nancy LC]

It is possible to eat low calorie yet not be starvingly hungry, I think we all know that. Its part of the magic of ketosis and keeping insulin under control. God knows, if I were eating 1000 calories a day on high carb, I'd probably go nuts too.

[Lisa N]

And when people talk about stuff like this, they are referring to scientific evidence that doesn't exist. Roberts is also doing that -- from a different angle. She's saying it doesn't exist in the first place, and basing her conclusions on that.

I see, so what she is saying here is that because there is no evidence (either way, I might point out; nowhere is she claiming either that there are studies that prove her correct) she can make whatever claims she wishes and nobody can prove her wrong? ;) That's pretty poor footing on which to pose any type of theory as generally theories are based on some sort of observation, not just a lack of evidence one way or another.

Logically it doesn't make any sense. Lean body mass is one of the major factors that controls metabolic rate (hormones also play a part but that's not part of the discussion at the moment); the less muscle you have, the fewer calories you burn daily. If you lose lean body mass (muscle) and regain mostly fat each time you yo-yo (ie you are not replacing the muscle that you lost), logically you must be slowing your metabolic rate to some degree. How much will depend on how much muscle you lose and if you ever regain it before the next cycle of weight loss/muscle loss begins again.
Yo-yoing is defined as repeatedly losing and then regaining weight (not just once) so taking a study where the participants lose and regain once without consequence doesn't prove that there are no long-term effects from repeating the process over and over.
Does this mean that weight loss is impossible for someone with a history of VLC and yo-yo dieting? No, but it may mean that they will have a much harder time losing weight and it will likely take them a lot longer than someone who never dieted before.

[ItsTheWooo]

There is some very interesting results that came out of a Minnesota study on the effects of semi-starvation that David Garner wrote about in a book about eating disorders. The men in the study did have lower BMR's during the study, and their BMR's increased once they began eating again.

Thank you.
This is what research shows: Metabolic slowdown is temporary. There is no evidence of permanent metabolic slowdown from yo-yo dieting.

There are two primary components to diet-related metabolic slowdown. The first is loss of TEF (thermal effect of food). Digestion takes energy, so if you eat less, your metabolism slows. Think of it as earning points/cash back/etc for using your credit card.
Some dieters think not eating enough will put them in "starvation mode" and that this is permanent. First of all, eating more to lose weight is like spending money on your credit card to save money. Yes, it's true that eating DOES yield some "payback" in TEF; but eating more to lose faster is like spending more on credit to save money. Changing what you're eating is another story, but assuming everything stays the same and just absolute energy is increased, the overwhelming majority of the time this will accomplish nothing but slowing your rate of loss.

The other component to diet-related metabolic slowdown is "starvation mode". Starvation mode is not determined by how much or when you are eating, people. First I should specify it's not a mode. It's a gradient. The body errs in favor of conserving energy; it does not enter a "mode". Second, the body decides whether or not to conserve or spend based primarily by how much absolute remaining potential energy stores it has available to it.
Or in other words, the body starts to conserve energy when you start pushing your weight too far below your body's "set point" or "comfort zone", and persist in restricted eating. This is really only relevant once you get into the lower weight ranges for your body. I don't mean a height weight chart; someone with a starting weight of 400 pounds likely will start to show the signs earlier than someone with a starting (natural) weight of 120 (obese people likely have higher "natural weights" due to creating/being born with more fat cells). The point it happens at is not important anyway, what is important is to realize that it is a shade of grey AND it is not determined casually on a meal to meal basis.
Our bodies are constantly erring in favor or against using energy for "extras"; the primary factor which will push us to the latter side (against) is long term trend of energy availability. Energy availability is more than how much you're eating; a morbidly obese person on a diet doesn't need to worry because he has plenty of energy available as fat on his body. But, if you're not eating enough and you're already too thin, then you will run into problems.


Because of these truths; it is not likely at all that metabolic slowdown related to dieting is permanent.
TEF increases immediately once you start eating more.
"Starvation mode" is something you don't even have to worry about assuming you are not going near the lower weigh ranges; and if you are, it will go away once weight is regained and intake is sufficient.

Please note this is assuming a person in otherwise good health. Uncontrolled insulin resistance and other chronic disease states are confounding factors, and do not disprove the truth of this statement (that conservation mode is energy-availability dependent, that MOST metabolic slowdown relating to dieting is caused from a loss of TEF, and that both problems are temporary). If someone gets older, gets more insulin resistant, eats a diet that exacerbates that, whatever... those are extraneous factors which are causing metabolic problems & contributing to weight gain, not because of metabolic damage from yo-yo dieting.

It is proportional primarily to They gained on average all the weight they lost plus 10%, but eventually lost that extra weight.

Again, thanks;
Once the body "recovered" it went back to normal.

However I believe that study also mentioned a caveat that there was a subgroup of men who did not return to normal weight and they don't know why.

My theory is that subgroup of men were genetically predisposed to insulin resistance. The post-diet binging burdened their bodies with high amounts of sugar. This "triggered" excessive amounts of insulin. Being subject to relatively higher amounts of insulin also triggered related tendencies to make fat cells, store fat, and lose insulin sensitivity.

Result? Higher weight after dieting & rebound eating.
This theory (that dieting leads to worsening of eating habits, which makes insulin sensitivity worse) would nicely explain why people tend to gain and keep fat after dieting. If we consider that proportionally more people who diet are likely to have insulin sensitivity issues (would make sense, that's why people usually diet - to lose weight.) it makes perfect sense that this cycle of dieting & rebound eating would lead to ever increasing weight (and worsening of the problem).
THe cycle can be stopped by controlling carbs; indeed many of us who were yo-yo dieters find for the first time ever we can maintain a stable weight. Even if we aren't successful losing without enforcing "effort" (to undereat)... at least we aren't gaining. I was gaining extremely fast before controlling carbs. My body had NO ability to maintain itself. This was without rebound eating, mind you. I can only imagine how fat I would have gotten if I did the low fat diet --> binge thing.

The most interesting aspects of the study were the psychological changes that the men experienced during semi-starvation and during the follow-up period, including obsessive thoughts about food and binge eating. A yo-yo dieter who keeps trying to lose weight on very low calorie diets is most likely doomed to a lifetime of irrational thoughts about food, leading to repeated rebounds in weight.

Right on;
But I think the insulin link also needs to be explored here, it's the "missing link".
Food obsession (from bouts of low fat dieting) is the catalyst behind the binging, sure.
Food obsession alone will not make the body continuously store more and more fat. As the (normal) men show; eventually binging stops once body replenishes lost weight (and some), then weight gradually goes down back to normal as the body comes out of "conservation mode". Some of the men didn't return to normal.

I don't think it's the continuous dieting that is fostering food obsession, which is the reason weight isn't returning to normal. For some people this may be (this is probably true for those who are trying to shed "vanity pounds" and keep on dieting, only to find they are winding up heavier). This does not explain why one maintains heavy weight long after dieting & binging stops. My mother, after stopping the Atkins diet, long after rebound binging stopped, still maintains a weight 5-10 pounds heavier than starting. Why?

This is not happening for overweight and obese dieters who typically get & stay fatter after post-diet binging. The variable of predisposition to insulin resistance/hyperinsulinemia explains this nicely. It is insulin which controls the process of gaining and keeping weight. Energy deprivation not only encourages one to eat a lot (which raises insulin levels) for psychological reasons (which you point out), but it does things to the body that make it more sensitive to the effects of insulin on fat. Someone already sensitive to this will gain weight and find it more difficult to lose it; someone less sensitive won't.

[ItsTheWooo]

Both muscles and fat can be used as energy reserve. So when someone loses fat and gains muscles at the same time, his body could see no reason to restre his fat back.

The conventional notion that fat is simply "useless extra" is long disproven. Fat is an endocrine organ, and a very important one. I simply don't understand this eccentric obsession with high muscle mass and zero body fat. IMO it comes from this emotional bias that leanness represents "efficiency" and fat represents "waste and complacency". It has no basis in biological reality; the body wants a healthy amount of muscle and fat.
Ironically, fat is more essential than muscle and if the body had to decide which is less essential, it would definitely say the big, showy, flashy muscles. That's why it is the state of fat which largely dictates (chemically) to the healthy body the state of muscle, and it is why the body replenishes fat first with bias to muscle, prior to energy restriction & tissue wasting. The body isn't stupid. It knows what it's doing by making us replenish fat in a hurry after bouts of restriction. Muscle comes back, eventually, but not before the essential fat.

Emaciated fat tissue stores have a profoundly negative effect on the body. The body fails to produce the chemical signals which control anabolism of healthy tissue, in an attempt to conserve the energy. Skin becomes dry, inelastic, and pallor. Bone building slows. Muscle tissue building also slows (see how fat controls muscle?). Without enough fat, everything else stops and slows.

This is also why when we start getting to the really low weight ranges, the body begins to shed muscle preferentially to fat. The body knows that when it comes down to it, it can do without strong muscles but it can't do without adequate fat. How ironic is it that it's actually our fat cells that are work horses which keep the body functioning by pouring out chemicals that affect our various body systems... most of our muscles (save a few - emaciation of heart muscle can be fatal) are just "nice extra" to help improve survival. Yet people have a reverse view.

The aesthetic/moral obsession with 0% fat, and high muscle mass, is not only a biological impossibility (save for those who abuse drugs and kill themselves trying to obtain it), but it is actually an unhealthy goal.

[kwikdriver]

I see, so what she is saying here is that because there is no evidence (either way, I might point out; nowhere is she claiming either that there are studies that prove her correct) she can make whatever claims she wishes and nobody can prove her wrong? ;) That's pretty poor footing on which to pose any type of theory as generally theories are based on some sort of observation, not just a lack of evidence one way or another.

I thought I said at the start, "You can't prove a negative." Perhaps I forgot, so I'll say it now: "You can't prove a negative." All you can do is infer from the absence of proof. Considering the absence of proof I've seen so far, I'm doing a lot of inferring. However, all you have to do to convince me is show me some evidence that this metabolic damage exists. Saying "You can't prove it doesn't exist" isn't evidence.


Logically it doesn't make any sense. Lean body mass is one of the major factors that controls metabolic rate (hormones also play a part but that's not part of the discussion at the moment); the less muscle you have, the fewer calories you burn daily. If you lose lean body mass (muscle) and regain mostly fat each time you yo-yo (ie you are not replacing the muscle that you lost), logically you must be slowing your metabolic rate to some degree. How much will depend on how much muscle you lose and if you ever regain it before the next cycle of weight loss/muscle loss begins again.

It takes a month or two of training and proper nutrition to replace muscle lost through diet -- something I'm quite familiar with through personal experience. It is, therefore, absurd to claim that muscle loss equates to "permanent metabolic damage" when you can put the muscle back on in short order. That's the best argument you have?

[Nancy LC]

For example, Ms. Roberts states that metabolism slows roughly 9 calories for each pound of muscle lost, but a pound of muscle burns between 25 and 50 calories daily. What compensates for the rest?


From what I've read, the number of calories that muscle burns has been vastly over-hyped.

[ItsTheWooo]

There was another article posted awhile back essentially saying the same thing.

http://forums.lowcarber.org/showthread.php?t=250433&highlight=metabolism

I did some research into how many calories a pound of muscle burns. First thing I run into are some of the non-medical bodybuilding sites claiming something like 30 calories a day (I think it was day). Then I started using scholar.google.com to search and found more credible sources saying something like 2-6 calories more than fat. Yes, fat does burn a small amount of calories, it isn't totally inert like we've been told.

Yea; that's why we get fat in the first place: to accommodate all the energy we are eating. Very heavy people have very high metabolisms for a reason. If fat tissue didn't increase need for energy, people who over eat would not become fat. The energy is going into fat stores; those fat stores are being maintained by the energy yielded to body from constant over eating.

It is one of my many "stupid diet myth" pet peeves that muscle burns sooo much more energy than fat just by sitting idle.
Building muscle and encouraging anabolism is another story: that does increase energy. By pushing your body passed it's natural hormonal/genetic "muscle set point" via conditioning exercises, you are increasing rate of muscle anabolism. This increases metabolism considerably. Lifting weights is the metabolic equivalent of gaining fat, but without any of the aesthetic/health drawbacks. Instead of that 500 kcal energy worth of food being converted into fat, the body will use that energy to fuel the building of muscle tissue. It's basically giving your body another option for dietary energy besides shunting it to fat; you can exercise and build more aesthetically pleasing muscle instead.

This is why men burn so much more energy than women; their hormonal profile is such that their bodies favor muscle anabolism (among other reasons). It increases their need for energy. Women's hormonal profile does not. If a woman and a man eat the same amount of food, the man will use the energy to nourish the muscle tissue; the body won't have a lot of "extra" that it can build fat with. On the other hand, women do not have the hormonal profile which favors muscle anabolism. So if a woman eats a similar amount as her husband, her body will have no use for the energy, and will default it into fat anabolism. Women tend to get heavier when in relationships, for this reason: they spend more time eating with their partner, and wind up eating more like him.

[ceberezin]

"Granted, metabolism slows a bit when you lose weight, but that's because you also lose a little of the muscle that helped support the extra fat," she adds.
There's a problem with this statement. You lose muscle on a low fat diet because the continuing high levels of insulin prevent the burning of fat stores, and lowering calories beyond energy expenditure forces the body to produce glucose by catabolizing muscle mass. People do not lose muscle mass on low carbohydrate diet because the lower insulin levels permit the burning up of fat stores and leave lean body tissue intact, providing you eat sufficient protein.

Ms Roberts makes the mistake of assuming that the only diet is a low fat diet. Traditional nutritionists cannot even accede to the existence of low carb diets. They pretend there's no such thing. So in her imagination, dieting necessarily causes muscle loss.

[Lisa N]

It takes a month or two of training and proper nutrition to replace muscle lost through diet -- something I'm quite familiar with through personal experience. It is, therefore, absurd to claim that muscle loss equates to "permanent metabolic damage" when you can put the muscle back on in short order. That's the best argument you have?

Okay...how many yo-yo dieters do you know who quit dieting and begin 'training and proper nutrition' between diets? Remember, we are talking abou the typical yo-yo dieter (or VLC) who loses 10-20 pounds, goes off the diet and back to how they ate before, regains 15-25 pounds (mostly fat from the study that I posted earlier), decides to go back on a diet because they can't fit into their clothes and repeats over and over? Keep in mind also that we are not talking about low carbers or those following a muscle sparing program..just your run-of-the-mill dieter who is losing a good proportion of muscle along with the fat.
Less muscle = slower metabolism. Even Dr. Roberts agreed with that. ;)

"You can't prove a negative." All you can do is infer from the absence of proof.

I've already agreed that you can't prove a negative, but neither can you pose a true theory (let alone confirm it) without objective evidence and observation. What Dr. Roberts is saying is, "I theorize that there is no long term damage because there are no studies that show there is (even though studies have shown a metabolic slowdown during dieting and a preferential rebuilding of fat over muscle afterwards)" rather than, "I theorize that there is no long term damage because I have measured metabolic rates in yo-yo dieters over a period of years and not seen any significant changes in metabolic rate that cannot be accounted for through normal age-related slowdown". The former I wouldn't accept as absolute truth (and stake my metabolism on it), the latter I would consider more seriously.
Inferring from the absence of proof is scientifically sloppy and lazy. You can't prove a negative, but you can prove that the reaction to a set of circumstances is not what was expected (in other words, you can prove that metabolism doesn't slow over a period of time in yo-yo dieters) What else can you do? Observe, form a theory based on your observations and then test that theory. Discard what is proven false and further investigate what is shown to be true.

[kwikdriver]

Ms Roberts makes the mistake of assuming that the only diet is a low fat diet. Traditional nutritionists cannot even accede to the existence of low carb diets. They pretend there's no such thing. So in her imagination, dieting necessarily causes muscle loss.

I think she was making a general observation about the way people actually diet, not the way people "should" diet. The fact is, most people who diet don't low carb, so her statement is true on its face. I've read a couple of research things from Roberts where she seems to support a low-glycemic approach to eating. I haven't read all her stuff, but I like what I've seen so far.

[Nancy LC]

Here's what I learned last time I looked into muscles and calories burned:

http://www.thefactsaboutfitness.com/news/cals.htm

Get an extra kidney if you really want to burn more calories!


Daily metabolic rate
Adipose (fat) 2 calories per pound
Muscle 6 calories per pound
Liver 91 calories per pound
Brain 109 calories per pound
Heart 200 calories per pound
Kidneys 200 calories per pound



Better yet, get a large array of kidneys and think harder. I wonder if skin burns any calories, its a big organ.

[kwikdriver]

I've already agreed that you can't prove a negative, but neither can you pose a true theory (let alone confirm it) without objective evidence and observation.

And yet you keep making statements that amount to, "Prove it doesn't exist."

Nancy and someone else, by the way, have posted things showing any metabolic slowdown from diet is quickly restored once "normal" eating is resumed. Is there any evidence whatsover on the other side? Nope.

Instead of playing silly games, I'm simply going to say the same thing: Where's the evidence showing that this permenent metabolic damage exists? If you believe it exists, show the evidence. You can prove a positive; as I continue pointing out, you can't prove a negative. Muscle loss due to caloric restriction isn't "permanent metabolic damage."

[zedgirl]

Didn't man evolve as a yo-yo dieter.......building up the fat stores in summer and then living off them during the colder months when less food was available?

[Nancy LC]

Neanderkins

LOL! Interesting sounding diet!

[Dodger]

I can see permanent metabolic damage if the dieting caused thyroid or pancreas damage. The improper functioning of those organs will change the metabolism.

[zedgirl]

LOL! Interesting sounding diet!

It's a cross between Neanderthin and Atkins :)

[VALEWIS]

There's a problem with this statement. You lose muscle on a low fat diet because the continuing high levels of insulin prevent the burning of fat stores, and lowering calories beyond energy expenditure forces the body to produce glucose by catabolizing muscle mass. People do not lose muscle mass on low carbohydrate diet because the lower insulin levels permit the burning up of fat stores and leave lean body tissue intact, providing you eat sufficient protein.

Ms Roberts makes the mistake of assuming that the only diet is a low fat diet. Traditional nutritionists cannot even accede to the existence of low carb diets. They pretend there's no such thing. So in her imagination, dieting necessarily causes muscle loss.

And a lot of people in this thread are doing the same thing and assuming that we are only talking about a low carb, high fat diet vs a low fat hi carb diet. There is such a thing as a low fat AND low carb, high protein diet. This diet is very low calorie, but the large amount of protein spares loss of muscle mass.
I am living proof of this. I was not losing on standard Atkins any more, so switched to low fat low carb, low calorie, hi protein...under 900 calories a day (lean meat and fat free dairy and lots of veggies)...at the same time I joined Curves and they do an impedance body fat measure. I was at Curves for 3 months, and during that time lost 14 lbs on the diet. I then left and they took another BF measure. The net loss of body fat was close to 90% of the net loss of body weight. So by eating high protein, but few calories, you can spare your muscle more than if you just ate low calorie across all macronutrients..

Val

[Lisa N]

Instead of playing silly games, I'm simply going to say the same thing: Where's the evidence showing that this permenent metabolic damage exists? If you believe it exists, show the evidence. You can prove a positive; as I continue pointing out, you can't prove a negative. Muscle loss due to caloric restriction isn't "permanent metabolic damage."

http://jcem.endojournals.org/cgi/content/full/87/6/2777

Recent evidence suggests that women with hypothalamic amenorrhea, particularly those with an exercise-induced disorder, may be in a calorically depressed state (18, 19, 20, 21, 22). Low energy intake is known to be associated with a decrease in resting metabolic rate (RMR) (23, 24, 25, 26). Work on obesity suggests that the RMR may remain depressed in obese individuals who maintain a body weight that is lower than their natural (obese) weight (27) and restrict their caloric intake to do so. Even women who maintain a normal weight may suffer an energy deficit; their normal weight is probably maintained by a decrease in metabolic rate (28). Animal models indicate that the repeated gaining and losing of weight or the combination of fasting and refeeding causes a heightened food efficiency that persists beyond the periods of deprivation, and studies of male and female athletes have confirmed this (29, 30

http://jama.ama-assn.org/cgi/content/abstract/260/1/47?ijkey=bc4de85c4275dc9fb32c0a4e6fc8ed3db55a9ce0&keytype2=tf_ipsecsha

This study examined resting metabolic rate in adolescent wrestlers to test the hypothesis that repeated cycles of weight loss and regain would be associated with reduced energy requirements. Energy restriction lowers resting metabolic rate in normal-weight and obese persons. Repeated cycles of weight loss and regain can increase food efficiency, defined as the degree of weight change per unit of food intake, in animals. Many wrestlers lose weight repeatedly as they "cut weight" for matches. This cycle of weight loss and regain may affect their resting metabolism. Twenty-seven wrestlers were classified as cyclers or non-cyclers based on their weight loss history. Resting metabolic rate was measured using indirect calorimetry and body composition was evaluated using six skinfolds. Cyclers and noncyclers did not differ in age, weight, height, surface area, lean body mass, or percent body fat. Cyclers had a significantly lower mean resting metabolic rate than noncyclers (154.6 vs 177.2 kJ/m2/h) (4.6 vs 5.5 kJ per kilogram of lean body mass per hour). There was a 14% difference between the cyclers and the noncyclers in resting energy expenditure (6631.8 vs 7702.8 kJ/d). Weight cycling in wrestlers appears to be associated with a lowered resting metabolic rate.

http://www.ajcn.org/cgi/content/abstract/49/1/93?ijkey=c002185dd3112974770844ef73ecc9d265a808f7&keytype2=tf_ipsecsha

[ItsTheWooo]

Low energy intake is known to be associated with a decrease in resting metabolic rate (RMR) (23, 24, 25, 26). Work on obesity suggests that the RMR may remain depressed in obese individuals who maintain a body weight that is lower than their natural (obese) weight
Awhile ago I proposed the theory (first introduced to me via adiposity 101) that once you've been obese; it's like having a disease that you must "control". If you've been hyperinsulinemic, eating excess of sugar energy, and your body has gotten to that point, it's not a reversible condition because it creates extra fat cells the body must maintain. The body may lose fat cells with time, and forum members proposed (and then proved ) that the body does eventually destroy excess fat cells.
But, if you do a weight loss diet, force yourself to lose stored fat (meaning the fat is not lost "naturally" by the body taking its time to do it)... the body will try to refill the cell. That slimmed obese people would have lower metabolic rates is not surprising at all. This is not evidence of metabolic damage; it merely proves what I already believed true (that people who've been obese have a "condition" and part of it involves having an abnormally high minimum weight).

If they regained the weight, would their metabolisms be slower than they were before the diet? That's the relevant question.


(27) and restrict their caloric intake to do so. Even women who maintain a normal weight may suffer an energy deficit; their normal weight is probably maintained by a decrease in metabolic rate (28).

Again, if a so called "normal weight woman" is actually weight suppressed, some metabolic slowdown can be expected... conservation mode explains this not metabolic damage.
Animal models indicate that the repeated gaining and losing of weight or the combination of fasting and refeeding causes a heightened food efficiency that persists beyond the periods of deprivation, and studies of male and female athletes have confirmed this (29, 30
Ok this is the first reference to weight cycling here so far. They say that weight cycling - restoration of weight prior to energy restriction - leads to metabolic thriftiness that persists afterward.
The question is, though, how long does it persist? Is it permanent? If so, why did the men in the semi-starvation study return to normal weight with time?

It really doesn't matter, anyway. What's pertinent to us as obese people who are hoping to become normal weight isn't whether or not metabolism returns to normal after weight is restored following restriction. Virtually all of us are still restricting and weight-manipulated.
What's pertinent to us is whether or not metabolism ever matches weight-matched naturally thin, unrestricted eaters with no history of obesity. Studies repeatedly show weight-suppressed obese people have slower metabolisms. Is this a permanent effect? Does it get better with time, and if so, by how much?

[Lisa N]

So by eating high protein, but few calories, you can spare your muscle more than if you just ate low calorie across all macronutrients..

But in light of what NancyLC posted above:

From what I've read, the number of calories that muscle burns has been vastly over-hyped.

Why would this be important? It would seem that if sparing muscle doesn't make much difference that any VLC would do. Not that I'm proposing VLC as a viable way to lose weight, but just posing the question. If it makes very little difference in the long run, why go to all the trouble to spare muscle? ;)

[Lisa N]

If so, why did the men in the semi-starvation study return to normal weight with time?

They only lost and regained once, not multiple times, so it's not a good comparison or proof that repeated weight loss/regain (yo-yoing) doesn't result in persistant lowered RMR. OTOH, the wrestlers in the study who cycled (lost and regained repeatedly) showed a lowered RMR even when at the same weight and BMI as those who were not cyclers.

[Nancy LC]

Why would this be important? It would seem that if sparing muscle doesn't make much difference that any VLC would do. Not that I'm proposing VLC as a viable way to lose weight, but just posing the question. If it makes very little difference in the long run, why go to all the trouble to spare muscle?
Because it could be muscle you really don't want to lose, like heart muscle. And I think many of us think muscle is kind of purty and useful for moving heavy objects.

I can see permanent metabolic damage if the dieting caused thyroid or pancreas damage.

I've never heard of low calorie dieting causing pancreas or thyroid damage. In fact, the only references I've heard regarding thyroid and dieting is both in terms of starvation and very low carb dieting. But nothing I ever led me to believe those were permanent sorts of alteration.

One thing that I think is a consideration. The body reacts to starving in much the same way as it does to low carbing. So while you're criticizing low calorie diets, you might doing exactly the same thing with low carb diets anyway.

[Lisa N]

Because it could be muscle you really don't want to lose, like heart muscle.

It could be, but do you have any studies that show that the body will cannibalize cardiac muscle when protein intake is not severely deficient and not utilize less important LBM tissues first?

[kwikdriver]

This clearly does not support the thesis of "permanent metabolic damage" from restricted calorie dieting:

http://jcem.endojournals.org/cgi/content/full/87/6/2777

Recent evidence suggests that women with hypothalamic amenorrhea...

Low energy intake is known to be associated with a decrease in resting metabolic rate (RMR) (23, 24, 25, 26). Work on obesity suggests that the RMR may remain depressed in obese individuals who maintain a body weight that is lower than their natural (obese) weight (27) and restrict their caloric intake to do so.

This is saying something everyone here knows and accepts: while in a caloric deficit, metabolism is depressed. It says nothing about what happens afterwards. No sign of "permanent metabolic damage" here.
And of course, the fact that the subjects of the research have a pathologic condition going into it makes the whole thing rather pointless for the purpose of this discussion, even if it did address the topic at hand. This sentence from the conclusion is particularly amusing:

Ballet dancers consistently weigh 10–12% below ideal weight and diet to maintain this low weight.

Underweight people who undereat and have a history of amenorrhea and have lost bone density have slower metabolisms than normal people? I think we've reached a "No duh" moment here.



http://www.ajcn.org/cgi/content/abstract/49/1/93?ijkey=c002185dd3112974770844ef73ecc9d265a808f7&keytype2=tf_ipsecsha

This is better, but an abstract. From what can I tell from the abstract, it's saying that people who lose weight have a lower RMR than the massively obese. Unless I can see the whole thing, and they've controlled for the effect of the weight loss itself in it but densely left it out of the abstract (is anyone that incompetent?), it looks like another "No duh" moment: an obese person burns more calories when obese than they do after losing weight. The things you learn...

They never said that these formerly obese ladies had RMRs lower than that of normal weight ladies who had never been obese, which actually would have been good evidence.

I'll give you a hand: there's way better stuff than this in the links beneath this abstract. Unfortunately, the things I looked at support my position, not yours, when I read through them. They all indicate a return to normal metabolic function with the resumption of a normal diet.

Examples here: (http://ajpregu.physiology.org/cgi/content/abstract/287/6/R1306)
This enhancement in metabolic efficiency was not altered with either 8 or 16 wk of weight maintenance, but it did resolve when the forced control of intake was removed and the weight was regained.

Here: (http://ajpregu.physiology.org/cgi/content/abstract/287/2/R288)

This elevated metabolic efficiency persisted throughout weight maintenance but resolved after 8 wk of regain.

And here: (http://www.ajcn.org/cgi/content/abstract/72/5/1088)

Energy restriction produces a transient hypothyroid-hypometabolic state that normalizes on return to energy-balanced conditions.

So I suppose I should thank you for providing the link.

As an aside, these two articles were also linked to below the abstract, which I thought were excellent, and support some of the points made above regarding the superiority of low glycemic eating:

http://jama.ama-assn.org/cgi/content/abstract/292/20/2482

http://www.jacn.org/cgi/content/abstract/18/2/115

[Lisa N]

This clearly does not support the thesis of "permanent metabolic damage" from restricted calorie dieting

And your evauluation on the study involving the wrestlers would be?

[VALEWIS]

Lisa said:
"Why would this be important? It would seem that if sparing muscle doesn't make much difference that any VLC would do. Not that I'm proposing VLC as a viable way to lose weight, but just posing the question. If it makes very little difference in the long run, why go to all the trouble to spare muscle? "

...what kind of difference? The difference it made to me is that most of my weight loss was fat. In the starvation studies they found that people lost a lot of muscle too. Why would you not care about this? People who starve themselves become fat-thin as they retain more fat percentage in the overall loss. People who spare their muscles just get leaner.
You can see and feel the difference.

Whether or not doing this type of diet repeatedly, as in the study done with the wrestlers, leads to a permanent lower RBM is an interesting question... I suspect that they did not recheck on the RestingBMR say 3 months later to see if this was a temporary effect. Unless they did recheck on it later I would say they haven't proven a thing. My guess is that in time the BMR would go back to normal, but that study may yet need doing.

[kwikdriver]

And your evauluation on the study involving the wrestlers would be?


I didn't see the wrestler thing. I suspect it's sample bias: the wrestlers who cut are generally losing muscle, because they don't have much fat to lose to begin with, if you know anything about wrestlers. So of course they are going to have lower RMRs than a wrestler who doesn't need to cut, because they will be relatively less muscular.

Again, like the thing with ballerinas, this isn't really relevant to the topic at hand. You're talking about highly trained athletes losing lean mass, and engaging in anorexic behavior to do it, compared to overweight people losing fat. It isn't the same thing.

[Samuel]

I have enjoyed reading all comments and like to thank you all. However I see that the science of medicine contains enough theory which can almost prove anything or its contrary! Let me add some comments here:

(1) What I know for a long time is that a pound of muscle requires 30-50 calories a day to be maintained while a pound of fat requires only 3. I can't remember my source for that.

(2) If you ask a construction engineer how to build a human structure using only materials which can be manufactured inside the body from the food we eat, he will most likely come up with the same materials our body is made of.

He will recommend building a frame (skeleton) of the hardest material which can be made. And since hard materials are always weak against shocks, he will recommend covering the skeleton with a material which is both rigid and elastic. So he will end with a structure made of "bones and muscles".

Also, if you ask an expert what would you use for a material which can be kept into the body as an energy reserve so it can be used whenever food becomes scarce, he would recommend the material which can store the highest amount of energy per gram. "Fat" is the material which our bodies can make and satisfies this requirement.

So, you may find plenty of secondary uses for bones, muscles and fat but in order to know the main uses for all, we must go to the principals.

(3) I believe that if Atkins diet has been the first diet in your life, you could have reached your perfect weight without the need to pay attention to how much food you eat regardless to how old you are.

[Lisa N]

I didn't see the wrestler thing. I suspect it's sample bias: the wrestlers who cut are generally losing muscle, because they don't have much fat to lose to begin with, if you know anything about wrestlers. So of course they are going to have lower RMRs than a wrestler who doesn't need to cut, because they will be relatively less muscular.

It's a possibility, but as the researchers were careful to measure BMI using calipers and 6 skin folds, not likely.

Cyclers and noncyclers did not differ in age, weight, height, surface area, lean body mass, or percent body fat.

I would have liked to see this followed up over a period of months or years to see if the difference persisted, but the fact that there was a difference between cyclers and non-cyclers is significant, I believe, especially given that wrestling season does not last all year. If the difference is pronounced (14% difference in BMR is quite a bit) in young men who yo-yo, how much more so will it be in women who repeat the process over a couple of decades?

[VALEWIS]

Here's some more recent research on this topic which refutes this idea of permanent change, Lisa.

Med Sci Sports Exerc. 1993 May;25(5):613-9.
Two seasons of weight cycling does not lower resting metabolic rate in college wrestlers.

Schmidt WD, Corrigan D, Melby CL.

Human Performance and Health Promotion Laboratory, Purdue University, West Lafayette, IN 47906.

Over the course of 2 yr, we prospectively studied the effect on resting metabolic rate (RMR) of multiple cycles of weight loss followed by regain in six weight cycling collegiate wrestlers (WC) (mean age = 19.0 yr) compared with 12 weight stable, physically active, nonwrestling controls (C) (mean age = 20.9 yr), whose body composition was similar to the wrestlers. Furthermore, during the second year of the investigation, a group of six nonweight cycling collegiate wrestlers (NWC) (mean age = 18.8 yr) were included in the analyses. The WC had previously undergone at least three seasons of weight cycling and continued this pattern during each year of the study. For the WC, RMR was determined by indirect calorimetry before and after a 6-month season of weight cycling for each of two consecutive years. A similar time frame was followed for measurement of RMR in the C, while for the NWC, pre- and postseason RMRs were measured only during the second year. During the 2 yr, the WC had significantly higher (P < 0.05) pre- and postseason measures of RMR compared with the C. A separate analysis comparing all three groups during the second year showed that RMR was not different for WC and NWC, and that RMR was higher for both wrestling groups compared with C. In this prospective study, weight cycling did not increase the thermogenic efficiency of collegiate wrestlers compared with either nonweight cycling wrestlers or weight stable controls, who were not wrestlers.

[VALEWIS]

And another.

J Am Diet Assoc. 1993 Sep;93(9):1025-30. Related Articles, Links

Metabolic and anthropometric changes in female weight cyclers and controls over a 1-year period.

McCargar L, Taunton J, Birmingham CL, Pare S, Simmons D.

School of Family and Nutritional Sciences, University of British Columbia, Vancouver, Canada.

OBJECTIVE: Women who diet to lose weight often regain the weight over time, and the cycle repeats itself. The objective of this study was to identify a group of female weight cyclers and to match them with a control group who had never consciously tried to lose weight. For 1 year, weight patterns, eating habits, metabolic parameters, and body composition were assessed to determine whether there was a relationship between weight cycling and these variables. DESIGN: Measurements were done at baseline and at 6 and 12 months. Changes in weight, diet, and exercise were monitored throughout the year. SETTING: All testing was done at a university physiology laboratory. SUBJECTS/SAMPLES: Nine weight cyclers with a notable history of dieting and food restriction were recruited. Subsequently, nine control subjects were selected and matched for age, height, weight, lean body mass, and exercise habits. MAIN OUTCOME MEASURE: The observational study included measures of 3-day diet records, skinfold and girth, serum glucose, insulin and triiodothyronine, and resting energy expenditure. STATISTICAL ANALYSES PERFORMED: The main variables were analyzed using a 2 x 3 (diet group x time) analysis of variance with repeated measures on the time factor. Comparison of the means was done by Tukey post hoc test. RESULTS: A 7-point satisfaction scale indicated that the weight cyclers were dissatisfied with their weight compared with the noncyclers (P = .03). Otherwise, there were no differences between groups in dietary intakes or the physiologic variables. APPLICATIONS/CONCLUSIONS: In the parameters measured, a history of weight cycling did not affect the metabolic profiles of the weight cyclers compared with the noncyclers.

[VALEWIS]

And:

Can J Appl Physiol. 1993 Sep;18(3):291-303.
Physiological effects of weight cycling in female lightweight rowers.

McCargar LJ, Simmons D, Craton N, Taunton JE, Birmingham CL.

School of Family and Nutritional Sciences, Univ. of British Columbia, Vancouver.

Repeated cycles of weight loss and regain are referred to as weight cycling. It is a practice of many athletes who must achieve a low body weight. The purpose of this study was to determine whether a history of weight cycling results in sustained metabolic changes. Healthy female rowers with a history of dieting and weight fluctuation (n = 7) were compared to a control group of rowers who had never dieted (n = 7). Anthropometric and metabolic measurements were done at pre-, peak, and off-season during a 1-year period. At peak season the weight cyclers restricted their food intake and lost 4.2 +/- 1.8 kg, and subsequently regained 4.0 +/- 2.1 kg in the off-season. This was different from the controls (p = .003), who maintained a stable body weight at all times. No other group differences were observed. Resting metabolic rate (RMR) and triiodothyronine (T3) changed with time (p = .001, p = .000, respectively) in both groups, which appeared to reflect changes in fat free mass (FFM), not body weight. Long-term metabolic changes were not observed in these athletes.

[Nancy LC]

It's the war of the conflicting studies! :D

[VALEWIS]

Not really...the older one was done on adolescents. The more recent ones on adults are all finding the same thing. There is a fourth one as well, but that might be overkill and I think the point is made re yo-yo dieting and its mythical effect of slowing down BMR.

[kwikdriver]

I would have liked to see this followed up over a period of months or years to see if the difference persisted, but the fact that there was a difference between cyclers and non-cyclers is significant, I believe, especially given that wrestling season does not last all year. If the difference is pronounced (14% difference in BMR is quite a bit) in young men who yo-yo,

I would bet, based on my experience with them, that as a group wrestlers who need to cut to make weight watch their diets more closely than do those who don't. There isn't enough information in this abstract to draw any conclusions about how good the actual research is; for example, it doesn't say when the measurements were taken, in season or out of season, and all the other research shows the metabolic effect of dieting takes a few months of normal eating to dispel. And as I pointed out, this isn't the same thing: highly trained athletes who are starting out lean and then diet are being compared to overweight people who are losing fat. Yet it's the best thing you, or anyone, has brought forward.

how much more so will it be in women who repeat the process over a couple of decades?

How much more? Decades and decades of research is available, out of all of it, you find one piece of extremely dubious quality, and it's a settled fact that this happens, when there have been about 10 pieces of much higher quality research adduced in this thread showing it doesn't? Something ain't right here....

[VALEWIS]

Ok, then here's the fourth study that as far as I can see was done two years later to refute the 1988 one Lisa posted:

Am J Clin Nutr. 1990 Sep;52(3):409-14.

Resting metabolic rate in weight-cycling collegiate wrestlers compared with physically active, noncycling control subjects.

Melby CL, Schmidt WD, Corrigan D.

Human Performance and Health Promotion Laboratory, Purdue University, West Lafayette, IN.

To determine the effect of multiple cycles of weight loss and regain on resting metabolic rate (RMR), we compared RMR between 12 weight-cycling collegiate wrestlers (means age 19.4 y) with a minimum of three previous seasons of weight cycling and 13 weight-stable nonwrestlers of similar weight and body composition (means age 20.6 y). RMR was measured before, during, and after a 6-mo wrestling season. Wrestlers exhibited a significantly higher baseline RMR compared with the control subjects (p less than 0.05). During the season when wrestlers had lost weight for competition, RMR was reduced (p less than 0.05) but was not significantly lower than that of the weight-stable control subjects. After a season of weight cycling and the final weight regain, the wrestler's postseason RMR was similar to preseason values and higher than the postseason RMR of the control subjects (p less than 0.05). Participation in numerous cycles of weight loss and regain did not lower RMR in these competitive athletes, as has been previously suggested.

[VALEWIS]

And (just in case you wanted to read another one)

Int J Eat Disord. 1996 Jan;19(1):5-12.
Effects of weight cycling on the resting energy expenditure and body composition of obese women.

Wadden TA, Foster GD, Stunkard AJ, Conill AM.

University of Pennsylvania School of Medicine, Department of Psychiatry, Philadelphia 19104, USA.

OBJECTIVE: Numerous reports have suggested that cycles of weight loss and regain (i.e., weight cycling) are associated with adverse health consequences, a concern that may lead some obese individuals to forgo weight control efforts. The present study examined whether weight cycling was associated with a reduction in resting energy expenditure (REE) and with increases in both total and upper body fat. METHOD: REE, body composition, and body fat distribution were measured before and after weight loss, and following full weight regain, in 12 women who before treatment had a mean (+/- SEM) age of 38.8 +/- 3.4 years and weight of 98.0 +/- 3.2 kg. RESULTS: At the end of treatment, patients lost 18.9 +/- 2.6 kg which was comprised of significant decreases in body fat and fat-free mass of 15.2 +/- 2.2 and 3.7 +/- 0.8 kg, respectively (both ps < .001). REE also fell during this time from 1,631 +/- 82 to 1,501 +/- 51 kcal/d (p < .03). All of these measures, however, returned to their baseline values when patients regained their lost weight. Body fat distribution was unchanged throughout the study. DISCUSSION: These results do not support claims that weight cycling adversely affects REE, body composition, or body fat distribution.

[VALEWIS]

HOWEVER, although we have put the yo-yo diet/resting metabolism myth to bed, there is another issue that hasn't been mentioned. There is some epidemiological evidence that an early history of severe yo yo can set one up for insulin issues. This is just being looked at now and the data is coming from things like results of famines as well. But that's another story.


Val

[kwikdriver]

HOWEVER, although we have put the yo-yo diet/resting metabolism myth to bed, there is another issue that hasn't been mentioned. There is some epidemiological evidence that an early history of severe yo yo can set one up for insulin issues. This is just being looked at now and the data is coming from things like results of famines as well. But that's another story.

There's also some evidence that extremely rapid weight loss shortens lifespan. But the yo-yo dieting/starvation mode thing is such an emotional issue that the fact that there are other things that should militate against extreme diets goes by the wayside.

[VALEWIS]

There are all sorts of confounding factors that are often not reported...e.g. if the person lost a lot of weight by eating in an unhealthy manner- e.g. all grapefruit or something like that. Or even if the rapid weight loss was due to famine or illness.

[Samuel]

Here's what I learned last time I looked into muscles and calories burned:

http://www.thefactsaboutfitness.com/news/cals.htm

Get an extra kidney if you really want to burn more calories!


Daily metabolic rate
Adipose (fat) 2 calories per pound
Muscle 6 calories per pound
Liver 91 calories per pound
Brain 109 calories per pound
Heart 200 calories per pound
Kidneys 200 calories per pound



Better yet, get a large array of kidneys and think harder. I wonder if skin burns any calories, its a big organ.

Thanks for this link. I used to know that each pound of muscle requires 30-50 calories, but this is most likely inaccurate.

According to a machine I have my muscle mass is between 130-140 lbs depending on the water retained into the muscles. A 40 calories/lb would mean 5,200-5,600 calories/day which is obviously impossible.

However, I think that in addition to the increase in "rest calories" muscle growth increases the amount of calories consumed during activity also. This is based on the reason a heavy truck requires more fuel to do the same movement a light truck does.

[Nancy LC]

I used to know that each pound of muscle requires 30-50 calories, but this is most likely inaccurate.
Yeah, I think that's what gets bandied about in the consumer sorts of magazines.

Those are the numbers from just day-to-day living, at rest I assume. I would imagine actually putting those muscle to work would up their energy requirements! Hey... maybe drinking all that water makes the kidneys burn more calories?

And if your body is breaking down protein you've eaten to rebuild or build more muscle, then it probably won't be able to convert and store it as glycogen, right? So there are benefits to having muscle, but it is more subtle than we think it is.

God knows, if it were as easy as burning 30 calories a day per pound of muscle, I'd be in the gym everyday you can bet!

[ValerieL]

According to a machine I have my muscle mass is between 130-140 lbs depending on the water retained into the muscles.

Are you sure about that? Or is it lean body mass of 130-140 lbs? I'm not sure what the reality is about the number of calories a muscle burns (though I tend to believe the 6-9 calorie information more than the 50) but we can't refute the 50 calories per pound of muscle hypothesis based on multiplying our lean body mass by 50 calories and saying that's too much of a daily calorie allowance which I've seen more than one person try to do. Lean body mass also includes non-muscle weight such as bone, skin, etc.

[Samuel]

Are you sure about that? Or is it lean body mass of 130-140 lbs? I'm not sure what the reality is about the number of calories a muscle burns (though I tend to believe the 6-9 calorie information more than the 50) but we can't refute the 50 calories per pound of muscle hypothesis based on multiplying our lean body mass by 50 calories and saying that's too much of a daily calorie allowance which I've seen more than one person try to do. Lean body mass also includes non-muscle weight such as bone, skin, etc.

They call it "muscle mass" (as printed on the machine and in the owner manual)

[Nancy LC]

I don't think there's any consumer machine that could possibly differentiate between muscle mass and other stuff. I wish though! I'd love to know my muscle %, fat %, water % and everything else!

[Samuel]

Mine does. It gives you all these numbers except that it shows numbers which make no sense! Here is a sample:

If I take measurments immediately before going to bed and immediately when I wake up then compare the two sets of measurments to see what happenes during sleep, I could get these results in a typical day:

I lose 4 lbs of water.
I lose 2 lbs of weight
I lose 5.8 lbs of muscles
I gain 4.3 lbs of fat

I can make sense of losing some water and losing some weight, but how can I gain fat or lose such a large amount of muscles during sleep? They say that muscles weight includes the water retained into them, but still this is not enough for an answer.

I paid $80 for this machine which is very cheap except that the machines Gold's Gym trainers use are cheaper! So I have no better choice. I'm not sure there is any machine on the market which can give more dependable readings.

[Nancy LC]

Sounds like you might as well have spent $5 and gotten a Crazy 8 Ball and asked, "Did I lose fat?" and go with that answer. :p

[BetyLouWho]

Sounds like you might as well have spent $5 and gotten a Crazy 8 Ball and asked, "Did I lose fat?" and go with that answer. :p
That's hilarious. I have a similar scale. I just use it for the mass measurement and don't even touch the other features.
This is my second attempt at a scale that would quantify fat loss. The first one had only three readings....which were basically these: Underfat, ok, overfat. How about giving me some sort of ruler to determine how far I am away from the magical level? I took that one back. This one has readings that are all over the place. Funny thing, at 5'9" and 238 lbs, in this configuration, I can be pretty certain that my body fat is "too high"!!:lol: Crazy 8 ball aside!

[Samuel]

That's hilarious. I have a similar scale. I just use it for the mass measurement and don't even touch the other features.
This is my second attempt at a scale that would quantify fat loss. The first one had only three readings....which were basically these: Underfat, ok, overfat. How about giving me some sort of ruler to determine how far I am away from the magical level? I took that one back. This one has readings that are all over the place. Funny thing, at 5'9" and 238 lbs, in this configuration, I can be pretty certain that my body fat is "too high"!!:lol: Crazy 8 ball aside!

I'm glad you have the same scale. I actually like it too. I have fixed most of the problems which I described above and I'm now using it every day.

If you like some math, here is how to get the numbers to even up:

The variations in muscle mass and fat% are mostly caused by the changes in body water. So I figured out the factors which can adjust the numbers to what they should have been if the body water% was 50% for all.

If the machine tells you that your muscle mass = M and your body fat% = F:

Your muscle mass adjusted to 50% water = M(1 - 0.018814 W) and

Your Body fat% adjusted to 50% water = F(1 + 0.06181 W)

Where W is the difference between the water% showed by the machine and 50.

So if the machine shows 52% water, W is = 2.

I'm not sure you'll like this, but if you do it, you'll be able to make more sense of your progress. Good luck.

Sam

[Samuel]

Both muscles and fat can be used as energy reserve. So when someone loses fat and gains muscles at the same time, his body could see no reason to restore his fat back.
The conventional notion that fat is simply "useless extra" is long disproven. Fat is an endocrine organ, and a very important one. I simply don't understand this eccentric obsession with high muscle mass and zero body fat. IMO it comes from this emotional bias that leanness represents "efficiency" and fat represents "waste and complacency". It has no basis in biological reality; the body wants a healthy amount of muscle and fat.

Sorry Woo, I did'nt notice this post in time. I did not mean that fat is less important than muscles. Here is what I meant:

At the end of a low calorie diet, your body can be saying "I'm lucky, my original energy reserve has allowed me to survive through this food shortage season. Since I know now how bad it could go, I must restore all my energy reserve and some extra to prepare for the next food shortage which can be worse."

Then you do muscle building exercise so your body says "Here is a new problem which must be addressed immediately. She is in need of doing a physical operation which is about to damage her muscles. I must use all extra energy to strengthen her muscles before all."

When your muscles become strong enough, your body says " Now she is in no immediate danger, let me return back to resoring my energy reserve (body fat)". Then your body discovers something and says "Here is an idea. Her new muscles can also be used as energy reserve for the next food shortage season. So, now I need less body fat than I thought I needed."

So by exercising you tricked your body. You made your body decide to reduce the amount of fat it likes to keep.

[nobimbo]

Just want to add to the excellent research already posted here. Here is a link to a discussion about weight cycling from Adiposity 101:

http://www.omen.com/adipos.html#adps45

Here are some excerpts:

The data of Bjorntorp and Sjostrom (METABOLISM V20;7;703) show a greater than 10 per cent increase in fat cell numbers from a single diet/partial regain cycle in some subjects with many fat cells. Fat cell numbers increased both during dieting (5%) and again during regain (5%). Subjects with fewer fat cells (normal range) did not experience this increase in fat cell numbers. The normal range is marked by the crosses at the lower left of the chart above.
A paper appearing in The American Journal of Clinical Nutrition found "all three measures [of weight cycling] were significantly related to BMI (P < 0.01)." (Am J Clin Nutr 1992;55;641-4)
In "Weight cycling: the experience of human dieters", Blackburn et al found a metabolic effect of dietary weight cycling, with slower rates of weight loss on a second diet. The Wadden/Optifast study on dietary weight cycling found a statistically significant correlation between dieting history and weight, BMI, fat mass, waist size, and hip size. The Wadden/Optifast study attempted to refute the Blackburn study by reporting that high diet cyclers lost weight as rapidly as low cyclers. Unfortunately, the high cyclers had three times the excess fat of low cyclers. Normally weight loss on a diet is strongly correlated with initial fatness, but Wadden's high cyclers, with three times the excess weight, only lost the same as the much thinner low cyclers. With half of their excess fat still remaining, Wadden's high cyclers reached a plateau and stopped losing weight on a 1000 calorie diet. (Am J Clin Nutr 1992;56;203S-8S)
The Framingham study also found weight cyclers to be much fatter.
To add injury to insult, dietary weight cycling may be bad for one's health. Weight cycling by dietary means may have a role in the development of chronic disease.
A study by Jeffrey, Wing, and French published in the American Journal of Clinical Nutrition "adjusted" (fudged) the health risk data to "account" for the increased fatness of the diet cyclers. This inappropriate data adjustment (IDA) is barely mentioned and never justified in the paper. This adjustment is unwarranted in light of the observation that "without effort to diet, weight changes tend to be small over long periods of time" (Western Journal of Medicine Oct 1990; 153;421) Adjusting for current weight begs the question that dietary weight cycling increases obesity. Applicants experiencing negative health outcomes associated with weight cycling were excluded from the study. As an alternative to such exercises in manipulation, adjusting for weight history before the subjects' first diet would be credible.
This and other studies that "adjusted" for weight gain did not report adverse results of weight cycling besides those commonly attributed to the excess weight from weight cycling. These negative studies are discussed in "Variability of Body Weight and Health Outcomes in the Framingham Population" by Lissner et al. With a cohort of 5127 and more detailed medical records, the Lissner study of the Framingham population supersedes the earlier, smaller, and more idiosyncratic studies.

The mechanisms by which dietary weight cycling leads to negative health outcomes have not been intensively researched, but some have been implicated:
Diet induced hypercholesterolemia (American J Clin Nut 1991;53;1404-10)
Diet induced depletion of Omega-3 reserves, believed to protect against colon cancer, heart attack, etc.. (Phinney, Am J Clin Nut 1992;56;781-2)
Diet induced replacement of linoleic and alpha- linolenic acids with saturates and monounsaturates. (Zhen-yu Chen, Stephen C Cunnane, Dept. of Nut Sci, U of Toronto)
Decrease in HDL ("good") cholesterol
Loss of heart tissue
Loss of bone mass (USDA Grand Forks Human Nutrition Research Center)
Increase in fat cell numbers (Bjorntorp and Sjostrom METABOLISM V20;7;703)
Changes in fat cell receptors
Another ominous outcome is that the weight that is regained is more likely to be in the upper body than the lower, and for men at least, that type of weight distribution has been linked to an increased risk of heart disease. (University of California Berkeley Wellness Letter, 5;4)
Some studies on human weight cycling are tabulated below.

Linda