Tuesday, August 11, 2009

The secret to losing weight

Recently people have emphasized the formula:
[calories eaten minus calories burnt] times 3500 = change in lbs of weight
Which is fine, and a useful tautology to start with, but people interpret this the wrong way.

Time magazine recently came down on the side that reducing calories eaten is all that matters, though others have argued that increasing calories burnt through exercise is all that matters.

The problem is that all of these things are missing a third factor, metabolism. which we don't directly control, but is probably far more important than the other two.

The typical American gains about one pound a year. That corresponds to 3500 calories.

That means over the course of a year where we typically eat around 1 million calories, the difference between calories eaten and calories burnt is only 3500, or or about 0.3%

I do believe that we probably have a fair amount of control over how many calories we eat (not complete, but fair). However, I find it hard to believe that somehow our conscious self manages our activity level to be within 100.3% of that calorie level. Clearly automatic mechanisms in the body are kicking in that regulates how fast we are burning calories.

Thus, as the Time magazine article points out, it is not at all clear that exercise increases calories burnt. It does while you are exercising, but if it causes those automatic mechanisms for metabolism to slow down for the rest of the day, then exercising would achieve nothing at all.

So that's the secret. Find a way to adjust that automatic mechanism and the path to weight loss is clear. Just don't ask me how to do that.

3 comments:

James Lin said...

The way that Calories are measured in food (total combustion) seems misleading anyway. Clearly there's energy we're not absorbing; poop is flammable, serves as an energy source for other organisms, etc.

OTOH, the way we measure Calories burnt isn't really accurate either, so maybe it balances out.

HoBs said...

hey, good point about the flammability of poop, no one ever mentions that. i should add that to the equation.

i remember being grossed out in grade school learning about how people use cow chips for fuel and how dung beetles use them for food.

Today, I suppose it would be considered a great green energy source.

Unknown said...

I see your point, though the part about the average American is misleading. For example, married men gain an average of 2 pounds a year, so that's bad news for you! I'd say the 1 pound a year number is just the result of a lot of noise averaging out, instead of being representative. I mean, my weight range in four years has been about 50 pounds, and it was definitely exercise that made the difference. 95% of people get back anything they lose within six months, so however autonomic metabolism is, it's not enough.