Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-ca

[hakimaj]

Just published:

Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.

Johnston CS, Tjonn SL, Swan PD, White A, Hutchins H, Sears B.
Am J Clin Nutr. 2006 May;83(5):1055-61. Related Articles, Links
Department of Nutrition, Arizona State University, Mesa, AZ.

BACKGROUND: Low-carbohydrate diets may promote greater weight loss than does the conventional low-fat, high-carbohydrate diet. OBJECTIVE: We compared weight loss and biomarker change in adults adhering to a ketogenic low-carbohydrate (KLC) diet or a nonketogenic low-carbohydrate (NLC) diet. DESIGN: Twenty adults [body mass index (in kg/m(2)): 34.4 +/- 1.0] were randomly assigned to the KLC (60% of energy as fat, beginning with approximately 5% of energy as carbohydrate) or NLC (30% of energy as fat; approximately 40% of energy as carbohydrate) diet. During the 6-wk trial, participants were sedentary, and 24-h intakes were strictly controlled. RESULTS: Mean (+/-SE) weight losses (6.3 +/- 0.6 and 7.2 +/- 0.8 kg in KLC and NLC dieters, respectively; P = 0.324) and fat losses (3.4 and 5.5 kg in KLC and NLC dieters, respectively; P = 0.111) did not differ significantly by group after 6 wk. Blood beta-hydroxybutyrate in the KLC dieters was 3.6 times that in the NLC dieters at week 2 (P = 0.018), and LDL cholesterol was directly correlated with blood beta-hydroxybutyrate (r = 0.297, P = 0.025). Overall, insulin sensitivity and resting energy expenditure increased and serum gamma-glutamyltransferase concentrations decreased in both diet groups during the 6-wk trial (P < 0.05). However, inflammatory risk (arachidonic acid:eicosapentaenoic acid ratios in plasma phospholipids) and perceptions of vigor were more adversely affected by the KLC than by the NLC diet. CONCLUSIONS: KLC and NLC diets were equally effective in reducing body weight and insulin resistance, but the KLC diet was associated with several adverse metabolic and emotional effects. The use of ketogenic diets for weight loss is not warranted.

PMID: 16685046 [PubMed - in process]

[Michelle H]

It was a 6 week study. I doubt those on the ketogenic diet had had time to become fully adapted to it.

I think this study will be widely quoted as it "proves" low carb diets are NOT HEALTHY!

Michelle

[LC FP]

inflammatory risk (arachidonic acid:eicosapentaenoic acid ratios in plasma phospholipids)

Hmmm, sounds like something Barry Sears (The Omega Rx Zone)would say. Wonder if that's him at the end of the author list? 40% carbs is about what the Zone recommends I think.

Despite that, this is pretty interesting stuff. Maybe it explains why my TC and LDL keep going up, even though my HDL is great and my cardio-CRP is almost unmeasurable.

[kwikdriver]

I just read this. Here's the link. Almost makes it worth buying a subscription to AJCN to read the whole thing.


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16685046&itool=iconabstr&query_hl=1&itool=pubmed_docsum

[hakimaj]

Hmmm, sounds like something Barry Sears (The Omega Rx Zone)would say. Wonder if that's him at the end of the author list?

I hadn't noticed that before - but I think you're right. The next time I'm at the UW medical library I'm going to pull the PDF of this article and look at study design and whole paper. Obviously, it showed the results that he wanted.
The abstract also doesn't quantify the "adverse emotional impact" of a ketogenic diet.

[ItsTheWooo]

So basically they compared 2 sets of relatively healthy, overweight people and found that very low carb vs reduced carb was of no benefit. That's such a flawed study and retarded conclusion. It's like taking 20 normal people and randomly casting half their legs and the other half bandaging them... and then concluding the casting isn't important because both groups legs worked relatively the same at the end of the study. DUH.

I know for a fact, to my body, 40% carbs and 30% fat isn't going to cut it. This is actually a little lower than what I was eating to carb up when I was going to test my sugar (I was eating 50% carbs and 35% fats I think). I was having hypoglycemic crashes after every meal. It was simply *impossible* for me to keep my sugar stable without submitting to eat a lot of food (during that experiment I gained logical understanding into why all uncontrolled reactive hypoglycemics must also be overweight; if you eat carbs it is simply not mathetmatically possible to eat a normal amount of food, calorie wise, while also keeping your sugar out of the red most of the day).

If 40% carbs is not sufficient to keep my insulin/glucagon balanced (prevent hypos), that automatically means it is not sufficient to keep my metabolism as high as it should be (insulin will be suppressing lipolysis and gluconeogenesis, creating energy pits experienced as lethargy and/or sugar crashes, thus suppressing metabolic rate). Therefore I know for a fact 40% carbs, to my body, does not allow for nearly as high a metabolic rate or energy state as much lower.

Get 20 hypoglycemics, 20 diabetics, 20 people with elevated insulin levels, 20 people with insulin resistance syndrome... THEN let's see whether or not 30% fats/40% carbs works as well as much lower and 60% fats/5% carb.

[mike_d]

So essentially they were comparing people on induction with people on OWL?

First off 20 subjects is not enough for a valid randomized study.

Humm ... "5% of energy as carbohydrate." I wonder how many grams/day that is and what was it?

"During the 6-wk trial, participants were sedentary, and 24-h intakes were strictly controlled." How, were they in prison? A cheat on LC has way more impact than a cheat on higher carb.

I wonder who funded this one-- the sugar institute?

[mike_d]

I think this study will be widely quoted as it "proves" low carb diets are NOT HEALTHY!Michelle
Yeah, at the least it reinforce the mainstream medical opinion that ketosis is bad and even dangerous.

I think they should have included a control group, and at least 10 people on a low-fat diet.

[LC FP]

I wonder who funded this one-- the sugar institute?
I think it's just Barry Sears, trying to prove that the Zone diet is better for you than Atkins.

[Jiggy Puff]

So essentially they were comparing people on induction with people on OWL?

First off 20 subjects is not enough for a valid randomized study.

Humm ... "5% of energy as carbohydrate." I wonder how many grams/day that is and what was it?

"During the 6-wk trial, participants were sedentary, and 24-h intakes were strictly controlled." How, were they in prison? A cheat on LC has way more impact than a cheat on higher carb.

I wonder who funded this one-- the sugar institute?

I think it is almost like comparing Induction to South Beach!

[deirdra]

The Zone had an "adverse emotional impact" on me - I was starving all the time and constantly thinking about food and how to balance blocks at my next meal!

[kaypeeoh]

We're all experiments of one. I was on the Zone Diet when it was first published. (Long before anyone heard of Atkins) I lost weight but got bored with trying to make every meal a balanced protein/carb. I'm back on it and losing weight again. I think part of the problem the first time was not having enough fat in the diet.

The Zone's basis theory is that eating every meal with a ratio of 0.7 protein too 1.0 carb suppresses insulin. Fat is considered inert because it doesn't affect insulin. Because the protein intake is linked to activity level, you aren't eating a huge amount. By balancing protein with carb my breakfast totaled around 300 calories. Lunch and dinner are similar amount. With two snacks added the total calorie intake per day is 1200 calories.

[kaypeeoh]

The stupid cat walked across my keyboard and stepped on the "Send" key before I was done. The point for me is that I'm not hungry on 1200 calories per day. I think it's because of insulin suppression.

On the Atkins diet I lost weight. The metabolic advantage made it easy to gorge myself. On the Zone I need a little bit more discipline. When I was on the Zone the first time my cholesterol was 160. When I switched to Atkins my cholesterol went to 230.

Right now my weight is 170 pounds. The Zone calculations puts my body fat at 16%. I never did that well on Atkins. Like I said, we're all experiments of one.

[ItsTheWooo]

The Zone's basis theory is that eating every meal with a ratio of 0.7 protein too 1.0 carb suppresses insulin. Fat is considered inert because it doesn't affect insulin. Because the protein intake is linked to activity level, you aren't eating a huge amount. By balancing protein with carb my breakfast totaled around 300 calories. Lunch and dinner are similar amount. With two snacks added the total calorie intake per day is 1200 calories.
Fat is inert, but it is not totally neutral ("just calories"). Fat has a profound role in regulating the metabolism. It provides a ready catalyst for lipolysis, which can suppress a body's tendency to make too much of its own sugar (which, I theorize, may be a reason people who are closer to the diabetic side of things find weight loss actually increases when they take oils). It delays gastric emptying, which balances metabolism by slowing the rate sugars enter the blood and satisfying hunger, thus decreasing future eating (and eating augments sugar itself).

I think the zone is a great low carb diet for a very active person, or an average person with a pretty good carb tolerance (that is the sort of person who can eat anything and feel pretty much the same). The ratio of .7 to 1 would never work for me or probably most carb sensitive people. I wish all I had to do was eat 14 g of protein to let me handle 20g carbs. Heh. I can't even eat a meal with 20 carbs and expect to feel top notch no matter what's in it. If it's things like fruits and berries and other low glycemic stuff I can handle a bit more, but rarely can I eat a 20 carb meal and feel good.
Also, it's way more than some simple formula of pro:carb. Fat is extremely important in dictating how much carb I can handle (as is vinegar but that's another issue ;) ). Fat (and vinegar) slow how fast the stomach empties, which greatly reduces how much insulin my body makes as well as my perception of hunger.

[kaypeeoh]

[QUOTE=ItsTheWooo]Fat is inert, but it is not totally neutral ("just calories"). Fat has a profound role in regulating the metabolism. It provides a ready catalyst for lipolysis, which can suppress a body's tendency to make too much of its own sugar (which, I theorize, may be a reason people who are closer to the diabetic side of things find weight loss actually increases when they take oils). It delays gastric emptying, which balances metabolism by slowing the rate sugars enter the blood and satisfying hunger, thus decreasing future eating (and eating augments sugar itself).

It's why I think the Zone failed for me the first time. I stuck with lean meats and ate little fat. I see that fat in the diet stimulates lipolysis, especially if there isn't a large amount of ready carb. But by Sears version, it's that protein/carb ratio that suppresses insulin, not the fat. Fat has no effect on eicosanoids, the real reason for the Zone's purported health benefits.

[ReginaW]

So essentially they were comparing people on induction with people on OWL?

First off 20 subjects is not enough for a valid randomized study.

Humm ... "5% of energy as carbohydrate." I wonder how many grams/day that is and what was it?

"During the 6-wk trial, participants were sedentary, and 24-h intakes were strictly controlled." How, were they in prison? A cheat on LC has way more impact than a cheat on higher carb.

I wonder who funded this one-- the sugar institute?

Sample size is definitely an issue with the study.....the full-text indicated those following the ketogenic low-carb diet did indeed keep carbohydrate low - 20g to start with recommended increase to 40g and an average 33g listed as what was accomplished during the study period.

I want to see what those participating in each arm ate though - the macronutrient mix alone isn't sufficient to understand the results seen in this study. Curiously there is no detail of trans-fats consumed, only total, saturated, poly and mono - when added up there is a SIGNIFICANT gap between the three combined and the total eaten. I'd like to see what they ate that provided what looks to be an insanely high intake of trans-fats!

Speculation at this point without seeing a sample menu though!

[tortoise]

I think in this study everyone had the same caloric intake, which is one of the reasons I think I dismissed it out of hand when I first read it.

8 or 9 years ago I went on the Zone and I had a great response, as far as cutting carb cravings, losing weight, etc, although I did need to eat a lot more fat than the original calculations said (which, in the first book anyway, Sears said to do if you're hungry). Later, though, that amount of carb restriction didn't cut it for me. I assume it was menopause/midlife - a lot of people become more insulin resistant at this time of life. Now I need to limit myself to something in the range of 40-70 grams of carb per day.

[rumford]

I don't know why you guys keep dragging in your personal experience. The article says that the use of ketogenic diets for weight loss is not warranted. You think you lost weight and you think you are healthier but this is a scientific article: the use of ketogenic diets for weight loss is not warranted. What else do you need?

[ojoj]

I havent read all the posts but I just wanna say that the advantage of a ketogenic diet for me is that it diminishes my hunger and keeps me in control of my appetite - other diets probably would have the same weight-loss effects, but I cant keep on them so its irrelevant

[LC FP]

rumford

There are lots of scientific articles out there. I don't think this single article means much by itself.

LDL cholesterol was directly correlated with blood beta-hydroxybutyrate (r = 0.297, P = 0.025). Overall, insulin sensitivity and resting energy expenditure increased and serum gamma-glutamyltransferase concentrations decreased in both diet groups during the 6-wk trial (P < 0.05). However, inflammatory risk (arachidonic acid:eicosapentaenoic acid ratios in plasma phospholipids) and perceptions of vigor were more adversely affected by the KLC than by the NLC diet.

Many people aren't too concerned with LDL cholesterol, as long as TGs are low. The AA:EPA ratio is something Barry Sears made up in his book Omega Rx Zone. It might mean something, but I havent heard it used by other researchers. Not sure what he means by perceptions of vigor. IMO he's just trying to bash Atkins and promote his books.

What kind of diet do you think your ancestors ate for 9 months each year for 200,000 years? I doubt they divided their plates into 30% fat, 30% protein, and 40% complex carbs.

By the way, sorry to bring in my personal experience but I did lose weight and I am healthier.

[ItsTheWooo]

I havent read all the posts but I just wanna say that the advantage of a ketogenic diet for me is that it diminishes my hunger and keeps me in control of my appetite - other diets probably would have the same weight-loss effects, but I cant keep on them so its irrelevant
I might have you confused with someone else, but didn't you say that you consumed 3k cals and never gained weight?

[pbowers]

i've posted the paper here (http://ca.geocities.com/paul.bowers/1055.pdf) .

interestingly, at baseline those on the ketogenic diet (klc) were on average 4kg lighter than those on the nonketogenic diet (nlc), but had higher BMIs and greater waist circumference. sears wouldn't have stacked the deck in his favor, would he?

btw, there is absolutely no way those on the ketogenic diet were following it. on a 1500-calorie ketogenic diet they only lost an average of 2.4kg over 6 weeks?

[ceberezin]

I don't know why you guys keep dragging in your personal experience. The article says that the use of ketogenic diets for weight loss is not warranted. You think you lost weight and you think you are healthier but this is a scientific article: the use of ketogenic diets for weight loss is not warranted. What else do you need?

I’ve also read published scientific studies that told me that persisting in a low carbohydrate diet would cause me to suffer a slow, painful death. My personal experience leads me to believe otherwise. If we believe every study that comes out, we would be doing somersaults. Personal experience is a perfectly valid reason to question a study.

The fact that Barry Sears is one of the authors of this study and that the results corroborate the message that’s made him a lot of money is not in itself reason to reject the study. It is, however, good reason to be skeptical of the study and to look for problems in the methodology and conclusions. I would be very surprised if we did not find some.

[kwikdriver]

I’ve also read published scientific studies that told me that persisting in a low carbohydrate diet would cause me to suffer a slow, painful death. My personal experience leads me to believe otherwise. If we believe every study that comes out, we would be doing somersaults. Personal experience is a perfectly valid reason to question a study.

There is also a lot of scientific evidence that low carbing has no harmful effects at all, and there always has been if you look in the right places.

One of the problems I have with "personal experience" is I never know whose to believe. Should I believe Dean Ornish? One of the all meat people? Just whose "personal experience" is the right one? Oh, I should just follow my own. OK, starting tomorrow, I'll try a vegan diet, because all the vegans swear it makes them feel wonderful, and I should ignore the science on it. After giving the vegan diet a while, I should switch to fruitarianism, and then to the Zone, and then to standard low fat, and then the SAD, and then maybe I should try the dessertarian approach, then all meat, then all starch, then traditional vegetarinism, and so on. Because personal experience trumps everything else, it means I have to personally try every single eating plan out there before deciding which is best for me, personally. I figure after about 100 years I'll have tried them all, and then I'll be able to pronounce which plan is best, personally speaking, of course.

[liddie01]

I think i shall look into this one-dessertarian :yum:

[mike_d]

btw, there is absolutely no way those on the ketogenic diet were following it. on a 1500-calorie ketogenic diet they only lost an average of 2.4kg over 6 weeks?
Yeah that observation stands right out for anyone with experience on the Atkins diet. I read one study that checked urine to verify ketosis-- that may be full of holes as well. Its not possible to break down body fat without producing ketones so all diets may be "ketogenic" to some degree.

[ceberezin]

One of the problems I have with "personal experience" is I never know whose to believe. Should I believe Dean Ornish? One of the all meat people? Just whose "personal experience" is the right one?
I was saying that personal experience is an adequate criterion for having doubts about a particular study. I never suggested that others' personal experiences should dictate what anyone should do or believe. Personal experience is admissible as evidence, but needs to be weighed with lots of other pieces of evidence.

The fact that there are no ketones present in urine does not mean that someone is not in ketosis. You could be producing lots of ketone bodies, but if you are burning up those ketone bodies, there will be no ketone bodies in the urine. During induction, when you start producing ketone bodies but your body is not yet efficient about using those ketone bodies as fuel, you will tend to excrete ketone bodies in the urine. Someone could be in ketosis and still not be turning ketostix colors.

[ojoj]

I might have you confused with someone else, but didn't you say that you consumed 3k cals and never gained weight?

Yep, thats me - but its all high fat so generally high cal. Maybe its the fat, maybe its the ketogenic diet, but I'm very rarely hungry!

I have actually cut back just recently cos I'm apparently perimenopausal and was put on HRT, I put on 10lbs in as many days. I immediatley stopped them and have now dropped back to where I was, but my waist measurement has gone from 25ins to 27ins - No big deal, but I'm trying to prevent a trend.

However, on any other diet I wouldnt have had the control or will power to just cut back.

Jo

[LC FP]

The fact that there are no ketones present in urine does not mean that someone is not in ketosis. You could be producing lots of ketone bodies, but if you are burning up those ketone bodies, there will be no ketone bodies in the urine.

ce-- I suspect this is true. If we knew for sure how the kidney handles ketones it could be more ammo for us in the diet culture war we always seem to be fighting. The kidney is a beautifully designed machine and I can't believe it would let us down.

The kidney glomerulus filters everything soluble out of your blood plasma, including glucose and ketones. This incipient urine flows through a series of tubules before becoming real urine that is collected in the bladder.

The incipient urine has waste products of course, but it also has lots of stuff in it that your body doesn't want to lose, so in the tubule cells it has specific pumps to pump back into the circulation glucose and amino acids and anything else important that might get filtered out of your blood. This is a great system, because anything your body doesn't need stays in the urine and gets excreted.

The tubule pumps can be overwhelmed, however. If your blood sugar gets much above 180, the amount of glucose filtered is more than the capacity of the pumps to reabsorb, and glucose apears in the urine. I guess this means our BS is not meant to go over 180 (the renal threshold for glucose).

I don't know if the tubules have a ketone pump, but I bet they do. Since ketones can be burned for energy it would be a waste to just pass (sp!) them out.

I wonder if anyone knows if there is a renal threshold for ketones? If there is, it could give us an idea of what the body thinks a "normal" level of serum ketones would be. It also would be ammo against those who say ketones are deadly.

[Lessara]

There is one big advantage to Ketogenic: Appitite Suppression.

Its what keeps me from cheating. Nothing does better.

[ceberezin]

Interesting point LC FP. Here's another speculation. The tubule pumps for glucose and ketone bodies could be the same. As you pointed out in a previous post, ketone bodies tend to supress glycolytic enzymes. Perhaps the absence of glycolytic enzymes and the presence of lipolytic enzymes would convert the tubule pumps from glucose to ketones so that the body would not lose a principal fuel source no matter what the fuel might be. The presence of ketone bodies in the urine during induction is a sign that while you are producing ketone bodies, the conversion to lypolytic enzymes from glycoloytic enzymes is not complete.

[LC FP]

The presence of ketone bodies in the urine during induction is a sign that while you are producing ketone bodies, the conversion to lypolytic enzymes from glycoloytic enzymes is not complete.

That could be, but I suspect that if there is a ketone pump, you overwhelm it during induction as you annihilate your visceral fat. :)