First want to say that I'm new to low-carb dieting (only 3 weeks in), but I've read through a massive amount of information advocating both sides. While I know there are holes both in the science behind dieting and weight loss and in my own knowledge, I can't help but be bothered by this idea of stalling and starvation mode and the fact that the body will refuse to burn fat.

The problem I have is the laws of thermodynamics. While I know these laws are typically misused, but usually it's by the low-fat advocates who think that Calories IN = Calories OUT with 100% efficiency, and they don't even understand the concept of entropy and ignore the 2nd law completely.

I think its also misused when it comes to starvation mode, and Atkins stalling.

The problem I have with the idea of 'stalling' or starvation mode, is that a human being is able to retain the same amount of physical activity, yet burn almost no calories because they are in one of these two modes. I'm not a scientist but it sounds like a clear violation of thermodynamics.

Now I totally buy the concept of changes in metabolism being affected by 1) your current weight, 2) your muscle mass, 3) your intake of calories, 4) the ratio of calories sources, 5) other medical issues. But I highly challenge the notion that your metabolism can change as drastically as claimed by some experts. In fact I find it impossible that you could have an abundance of fat in your system, drop your calorie intake to 500/day, and suddenly your body is N times more efficient at burning calories as it was before such that it can still provide the same amount of physical work.

The only time I can even imagine a starvation mode where your body refuses to burn its own energy stores is when the person is literally dying and doesn't have any stores left! But along with that comes the absolute inability to be physically active. You can't do physical work without the energy to fuel that work.

Just picture this scenario. I am 6'1" at 190 lbs so I'm "slightly" overweight. I lift weights 2-3 times a week and run about 4 times a week. I probably burn 3000 calories a day. If I suddenly dieted for 1 month eating 500 calories/day and went into 'starvation mode', are you telling me that I MIGHT not lose weight? Suddenly my body is 6 times as efficient because I reduced calories below some threshold? If that's the case, where the heck is my energy coming from? I know people who have dropped their calorie intake that low and still had enough energy to work out. The only explanation for this is their ability to burn fat stores.

Now what I think is happening with both starvation and stalls is that more than likely its the body in a panic mode and trying to fill the fat void with water. I think this was hinted by the semi-starvation study that's been posted here and other places. The problem with a lot of these studies not being as conclusive in this regard is that the time-frame is often too short, and also it is unethical to mal-nourish someone and/or starve them as part of a study. But I'm sure if you put it to the test, you could find that they are in fact losing fat and that water retention becomes extreme when fat is lost rapidly.

The only other likely cause for stalling I also see is actually under-estimating the amount of calories they eat.

I'm not trying to pick fights, but this is my hypothesis using mainly common sense but admittedly I don't have a strong science background. If someone can explain how a person can become a several orders of magnitude more efficient machine by simply cutting calories, please enlighten me.

You're treating "cals in" and "cals out" as variables that are independent of each other.

What if they're not?

You're also assuming that the hormonal environment, which drives bodily reactions that ultimately enable us to run around and lift those weights, stays the same regardless of cals-in or cals-out.

What if it doesn't?

People eating 1,000 calories, 90% of which is carbohydrate, can gain weight. The same people eating 1,000 calories, 90% of which is fat, can lose weight.

Humans aren't bomb calorimeters, and as you say, CICO ignores entropy--among many other things! lol Humans also are definitely not closed systems, which is where the 2nd law holds. It holds in the system of our universe, but it does not hold in the system of our sun: the system of the sun loses E to its surroundings (enabling us to live).

There's no violation of the 2nd law here---only misinterpretation and misapplication. See also Feinman's blog.

Also, consider reviewing the following subjects, especially on thermodynamics:
General Chemistry
General Physics
Biochemistry

(NOTE: Old editions would be fine for thermodynamics and rudimentary understanding).

ETA: 2 LOBSTERS!!

What do you mean that I'm treating cals IN and cals OUT as being independent variables? All I'm saying is that there is an energy cost for the work that the body needs to do. I am skeptical that a body which normally requires 3000 calories to do XYZ has the ability to adapt such that it can still do XYZ but with only 500 calories. I don't think being a complex hormonal system accounts for that. And I have found some sources on the web that are just as skeptical, so I'm not the only one.

Also the study you linked to doesn't really tell me anything about fat loss. Just body weight over several days time. If someone is retaining water on an extra low calorie diet, it doesn't show there.

I actually ordered one of Taube's books by the way, just haven't received it yet.

Google "Taubes Zucker rats" and add them to what you are trying to understand.

Where in the world did you find this nonsense about 500 calories a day???? I can't imagine that would work for anyone.

I'm not sure what you mean can you elaborate? I am talking hypothetically in case you didn't know.

Have you read Tom Venuto on starvation? He's a calorie guy that acknowledges that the burn rate (metabolism) changes based on diet and exercise. In particular the phenomenon where a certain mix of exercise and diet depresses metabolism. Not to the degree of 3000 calories to 500 though I don't think.

http://www.burnthefatinnercircle.com/public/378.cfm

I have never seen a study that says a person can do the same work when calories from diet are either 3000 or 500. I suppose it would be possible. A young healthy man would probably be able to live off stored fat and muscle for quite a while still doing the same work on drastically reduced dietary calories. In that case the calories would be coming from stored energy, so the calories available for work might still add up to 3000. In that case the RMR might get depressed to compensate.

while you are male and probably don't face triggering autoimmune hypothyroidism (hypothetically) by going down to 500 calories a day, being that you are human (hypothetically) and NOT a grinch, you would run the risk of your thyroid NOT converting any of it's T4 into ANY T3 (the active part of thyroid hormone, which certainly has a say in metabolism) hormone.

Which is why many WOMEN who've done 'extreme dieting 101' are facing autoimmune hypothyroidism and thus have a slower metabolism (although this phenomenon is not 'scientifically' a part of 'starvation mode').

Most women will talk starvation mode ALL day long and NEVER realize that roughly two out of every ten women in teh USA alone have TPO antibodies...most will go on to have Hashimoto's hypothyroidism after a 'hormonal event' in their lives, but many 'trigger' those antibodies through crash dieting.

Just sayin'

Yeah, I figured that part.

Why are you asking this question here? Do you honestly expect a scientific answer to your wildly hypothetical question?

I haven't seen his work yet but i'll take a look. I don't have a problem with changes to the metabolism due to various factors, I just have a problem with the notion that your metabolism comes to nearly a grinding halt because you aren't eating enough calories.

The premise of my OP is that conventional wisdom says if you eat less than around 1200 calories a day, your body will resist burning fat because it enters a state of starvation. But when you are say 30 lbs overweight and physically fit, I don't see how you can continue exercising and suddenly stop burning fat. So if someone is reducing calories to only 500 a day, the only way the body is truly only burning 500 (hence no weight loss), is if the person is so ill they can hardly move. That would only be the case if the body was literally starving or had some other medical problem as a result of malnutrition. But that would take a long time for someone who is 30 lbs overweight to get to the point of true starvation.

It might be the only time of the year the Grinch can ask questions. (Hypothetically).

Leave the little dog alone, too.

There's nothing wild about it. There are people who eat little to nothing in order to lose weight. I am just challenging what is accepted in the scientific community as fact.

This is the 'Low-Carb War Zone', isn't it?

Actually, if you DID go down to 500 cals and you still continued to work out, wouldn't you be burning muscle, and not just 'fat' and especially considering how only 'newbies who lift' generally lose BOTH bodyfat AND gain muscle?

I did BFFM when I first started working out with weights...and Venuto charmed me immediately with the writing But I really got kind of 'bummed' after the newbie phase when I couldn't do the 'two step' trick (burn bodyfat AND gain muscle at the same TIME).

I don't dispute that. Its really how much of a change it would have on the metabolism that I dispute.

I also question all the people who eat very little on Atkins but stall. Is there any evidence that the person is truly not burning fat even though their calorie intake is likely much lower than they need?

I mean---what if (1) calories in affects calories out, and (2) calories out affects calories in: eating more calories causes expenditure of more calories; and expending more calories causes eating of more calories.



What besides a complex system can possibly account for it? One answer is that the "system" is not exactly the same for the 3000 cal scenario and the 500 cal scenario.

It depends on what XYZ are. If to the body, X > Y > Z in importance, then the body that requires 3000 cals to do X+Y+Z but now only gets 500 cals, may only do X. But if the body continues to do XYZ on 500 cals, it may make several other changes, such as eliminating ABCDEFGH and cutting XYZ down to a minimum. These changes create a totally different system than the original, in other words, a different physiological environment on the latter (500 cals) than the former (3000 cals).

If Y or Z is exercise (voluntary large muscle movement), consider how efficient our large muscles are in terms of energy expenditure.



Cites please. And be skeptical of the skeptics (it's fun).



You didn't read the whole study. They differentiated between lost body water, lost body weight, and lost LBM, iirc. (All together these allow deductions about lost body fat.)

I hope you enjoy it. And be skeptical of what you read (because it's fun).