Comment by Eliezer | Hacker News Reader

Comment by Eliezer | Hacker News Reader

This old lie again? This study just shows that four attempted diets, none of them particularly sophisticated, all work equally well - which is to say, not very.

Yes, the laws of thermodynamics hold, but what if, oh, say, what you ate had an influence on how much you felt impelled to eat? Or how energetic you felt and how much you moved around? If your fat cells are rapidly absorbing what's in your bloodstream, you'll feel hungry and eat more, and you'll feel tired and move less.

The number one experimental result of dieting is that 95% of the people gain back the weight a few years later.

If Seth Roberts is right, all we're seeing from this study is a temporary bump that results from changing your food habits in any direction, which leaves behind the old flavor-calorie association, which makes you less hungry. And if they stick to this diet a while, they'll develop new flavor-calorie associations and gain back the weight. (This is a very elegant theory which, among other experimental support, explains a lot of the chaos in dietary science; almost any dietary change makes you lose weight, but only temporarily.)

Sorry, metabolisms are just more complicated than this. Call me back when they test Loren Cordain's or Seth Roberts's theories.

Applying the 80/20 rule, metabolisms most certainly are not more complex than than a simple input/output equation for a vast majority of people.

We have been around in this planet for thousands of years, a vast majority of which spent by a vast majority of people in a non-obese way. Evolution has tuned our bodies not to be overweight so long as we don't change the equation of calories in to calories expended.

Our modern North American lifestyles have adjusted both sides of the equation, hence, obesity is an epidemic. Adjusting the equation back is a huge step forward, regardless of outliers.

Look at the military. Diets aside, the simple reason there are no large obesity issues within the organization is that they purposefully modify the output side of the equation. Diets don't work because the modification to the input side is always only a temporary change.

We eat too much and move too little. Duh. While the dynamics become more complex at the elite athlete level, and there is a segment of the population that could be considered outliers, if we all simply made the equation balance, we'd see a huge drop in obesity rates.

It isn't rocket science.

It still complicated, though. For example, eat 1500 calories a day while your metabolism uses 1800 or so. Sounds foolproof? What if those 1500 calories are all sugar? There goes your metabolic rate and your body fat will go through the roof. What if you eat 60% protein, 30% fiber, 10% fat? You will probably wind up looking like a career athelete, even if you never exercise. The composition of the calories has a huge effect on their usage (through the mechanism of you hormone feedback systems). It may not be rocket science, but the body is complex to the point of being a black box for most people.

I don't think anyone denies there is a huge part of dieting that is changing habits, lifelong habits. But most of them are just methods of consuming fewer calories.

Most people would have an easier time losing weight if they just stopped eating before being full. Being full should be a luxury, not a daily occurrence. All the studies about "obesity genes" are more focused around the appetite, not anything about metabolism. Appetite is a feeling, sometimes in life your feelings are not always the best method to drive your actions.

Why did you pick those two particularly?

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