Why Exercise Won't Make You Thin

Self-restraint is a hackable psychological phenomenon in one's brain. I agree that it is not an innate moral power, but I disagree that it is a distinct human quality that can be strengthened. Self-restraint boils down to optimism. People can put themselves through anything if they have faith that it will pay off in the end. Rational knowledge doesn't help, and it isn't a matter of simply being harsh with oneself, either: harshness and pessimism just produce a paralyzed, chubby, self-loathing person. If passing up a cheeseburger leaves you with a dead feeling inside -- "I'm deprived now and screwed in the long run anyway, what a waste" -- then you won't be able to keep it up. If you have faith that passing up the cheeseburger will have a long-term payoff, then your brain gives you a down payment of happiness that cancels out the displeasure of depriving yourself.

That's why thinking about a distant, glorious end result (like a smoking hot beach body) works for some people but is counterproductive for others. It's motivational if you really believe in it. For many people, though, it's just a reminder that they're making sacrifices for something that they don't believe in at all. Those people are better of thinking of less distant payoffs that they can really believe in, even if the payoffs are trivial by comparison.

Some people think that your brain will simply not accept passing up food that your body thinks it needs, that it's completely unnatural and therefore impossible. But you do things all the time that have energetic costs and distant, uncertain payoffs. Hard work, saving money, hell, even just getting out of bed: these are things that impose immediate costs. Your brain does emotional bookkeeping to incline you to avoid costs that have no payoff. If you've ever been depressed, you know that getting out of bed is sheer misery if you believe that nothing good will come of it. Yet it's normal to get out of bed, get to work on time, and work at a job for a payoff that comes a few weeks later. (Or, for a startup, months or years later.) In the same way, it can be normal to pass up food. You just have to have faith in the payoff. You might think that food has some special status in your brain, and it might, but your brain is surprisingly abstract and adaptable. (Consider the recent article about money!) Also consider that physical labor is basically the opposite of food, but people manage to habituate themselves to physical labor despite the complaints of their body (which are, initially, totally out of proportion to the physical cost.)

Having faith isn't easy; in fact, it's really hard. But it demystifies the question of why people eat or don't eat, and why they feel good or bad when doing so. I find it much easier to deal with my "faith" than to struggle directly with my impulses.

EDIT: Hmm, I got upvoted while in the process of making a major revision. Sorry about that. I should stop using the "edit" page for preview/composition.

This comes up in Hacker News every time a health story comes up, usually quoting a pop-sci writer. You've stated it by far the clearest with no vagueness or handwaving so hopefully you can answer this (or provide pointers to research):

In this theory where does the stored energy (i.e. the fat) come from if not from the calorie intake? How can this be done for more than a short period of time (e.g. I know you can break down muscle for energy) without breaking laws of physics?

The article does address this to some extent. For example:

"According to calculations published in the journal Obesity Research by a Columbia University team in 2001, a pound of muscle burns approximately six calories a day in a resting body, compared with the two calories that a pound of fat burns. Which means that after you work out hard enough to convert, say, 10 lb. of fat to muscle — a major achievement — you would be able to eat only an extra 40 calories per day, about the amount in a teaspoon of butter, before beginning to gain weight."

Running an hour a day is a dicey proposition because of the possibility of injury. I would say it's impossible for the vast majority of people who are overweight, no matter how carefully they worked up to it. You'd have to be skinny, have excellent form, and not have any unfixable pre-existing injuries or weaknesses.

The problem is that every few weeks an article comes out with some blanket statement like this, like "Excercise won't make you thin" which is only a partial truth. If you read many articles about fitness and nutrition you'll realize that there are no black and whites when it comes to nutrition and weightloss and there is no one easy answer.

Staying healthy and losing weight is a combination of good habits.

The reality is of course that exercise is a fantastic way to lose weight and stay healthy, but as this article says if you don't pair that healthy eating habits it means absolutely nothing.