[swerling]

While the article does not go into specifics about the "Science" involved, it is not hard to find hard science that show unequivocally that only lowering calories lowers weight, eg. this one from the New England Journal of Medicine: http://content.nejm.org/cgi/content/full/360/9/859. Why is the first law of thermodynamics so hard for people to internalize? Shall we start measuring the energy in stars in terms of grams of fat too? One expects this kind of thing on Oprah, not on HH.

At any rate, let's assume for a moment that the blogger is still eating the same number of calories, and doing the same amount of weight lifting (that is, still burning the same number of calories), but he is still losing weight. To be consistent with the 1st law of thermodynamics, it will mean he has made his body less efficient at absorbing the calories in food. So he has successfully shocked his metabolism into being less efficient. Will he stay on this diet forever? Because as soon he starts eating bread again, presumably his metabolism will emerge from the state of shock he induced. When that happens, while he will feel as if he were eating the same amount of calories, he will effectively be eating much more since his metabolism will no longer be so inefficient.

[chandler]

Different nutrients are processed differently by the body, fully in line with thermodynamics.

Take 100 Calories of sawdust (cellulose). If you eat this, how many calories did you consume? Did consuming these calories contribute to fat accumulation? Because the answer to this is no, does this cause a violation of the 1st law?

Your body doesn't merely "absorb calories" from food. It absorbs and transforms chemicals, and directs these chemicals through various pathways. Eating a low carbohydrate diet doesn't "shock his metabolism" into being less efficient, it simply uses different pathways for nutrient absorption.

Also, regarding the referenced study: All four diets tested were virtually identical regarding the % calories derived from fat, protein, and carbohydrate.

http://content.nejm.org/content/vol360/issue9/images/large/0...

Moreover, the low-fat diets weren't particularly low-fat, and the high-fat (low-carb) diets weren't particularly low-carb.

So what happens when you feed a group of people the same 1600 Calorie diet for two years, and then measure their weight loss? What exactly are you demonstrating?

[nova]

Why is the first law of thermodynamics so hard for people to internalize?

The first law of thermodynamics stablishes a relation between energy input, energy output and energy storage. It does not say which variables are independent, ie, the direction of causality. The theory of low-carb diets is that carbs affect energy storage via insulin first leaving a constraint bewteen energy in and out, not the reverse.

Also note that in the article cited the lowest amount of carbs was 35%, which still is a moderatelly high amount. And the result seems to be very modest (about 4kg lost only).

[stonemetal]

So then there is no reason for any type of sort beyond bubble. After all it is data in data out right? The human body is a bit more complicated than sorting algorithms. When you eat a no carb. diet interesting things happen the least interesting of which is that protein takes more processing to turn into energy than sugar does. One of the most interesting,(from a dieter's perspective) is that the body enters a state called ketosis in which excess protein is expelled from the body instead of being stored as fat. This makes your body self regulate its weight. Second eliminating sugar from your diet makes you less hungry since your body experiences less blood sugar variation.