Why most of us believe that exercise makes us thinner—and why we're wrong

[cvictorg]

Does Exercise Really Make Us Thinner? -- New York Magazine

The job of determining how fuels (glucose and fatty acids) will be used, whether we will store them as fat or burn them for energy, is carried out primarily by the hormone insulin in concert with an enzyme known technically as lipoprotein lipase—LPL, for short. (Sex hormones also interact with LPL, which is why men and women fatten differently.)

In the eighties, biochemists and physiologists worked out how LPL responds to exercise. They found that during a workout, LPL activity increases in muscle tissue, and so our muscle cells suck up fatty acids to use for fuel. Then, when we’re done exercising, LPL activity in the muscle tissue tapers off and LPL activity in our fat tissue spikes, pulling calories into fat cells. This works to return to the fat cells any fat they might have had to surrender—homeostasis, in other words. The more rigorous the exercise, and the more fat lost from our fat tissue, the greater the subsequent increase in LPL activity in the fat cells. Thus, post-workout, we get hungry: Our fat tissue is devoting itself to restoring calories as fat, depriving other tissues and organs of the fuel they need and triggering a compensatory impulse to eat. The feeling of hunger is the brain’s way of trying to satisfy the demands of the body. Just as sweating makes us thirsty, burning off calories makes us hungry.

 

[dfein]

It's common sense really. Exercise does make you thinner by partitioning the calories differently. And it's only untrained people who get hungry after exercise. Exercise often causes a rise in norepinephrine levels which usually causes a decrease in appetite. Two twins eat exactly the same amount of calories while one exercises (making sure to fill the deficit), the twin who exercises will be in better shape.

 

[cvictorg]

It's common sense really. Exercise does make you thinner by partitioning the calories differently. And it's only untrained people who get hungry after exercise. Exercise often causes a rise in norepinephrine levels which usually causes a decrease in appetite. Two twins eat exactly the same amount of calories while one exercises (making sure to fill the deficit), the twin who exercises will be in better shape.

So - what about LPL response to exercise?

 

[Millard]

Does Exercise Really Make Us Thinner? -- New York Magazine.

Of course, weight loss is not simply "burn calories, lose weight"

Weight loss is usually the result of many variables, not just exercise.

Most people involved in bodybuilding see "exercise" as the solution to GAINING weight.

I've been exercising on average 5-10 hours per week for over 20 years -- with a net gain of 60 lbs.

Does that mean exercise is useless for losing weight?

No, not at all.

Exercise is a tool - that can be used to accomplish various goals - and whatever the goal, it is not generally used in isolation to achieve that goal.

 

[LW64]

Gary Taubes original (2007) article on excercise and weight loss:

Does Exercise Really Make Us Thinner? -- New York Magazine

 

[ergomaniac]

im sure genetics are involved. and perhaps the machine you build in your youth contributes. and putting shitty gas in lamborghini makes it run shitty. eating and nutrient timing are a big part of what we do here. my diet is pretty structured, and tailored towards my goals. my workouts usually last less than an hour. the rest is replenish, rebuild and relax. different foods illicit different reactions and are used and stored in different ways. calories in - calories out doesnt work. and what passes for exercise these days to appease the unmotivated and weak is disheartening. a little effort people.