I heard a radio program a few years ago about childhood obesity. They had an expert on who said something I'd never really thought of before: They said the conventional causality of sports curing obesity is the wrong way around. The reason you don't see fat marathon runners isn't because running makes you thin, it's because being thin makes it easier to run.
The guy's reasoning was: You exercise for an hour doing something like walking or golf, then reward yourself with a snack? Net intake of calories [1]. And it's easier to cut a snack from your diet than to find the time and motivation to do an hour's exercise.
To put it another way, when you're obese exercising is like a job that pays ten cents an hour.
Of course, once you've become thin and athletic, you gain access to more time-efficient types of exercise. But that snack might still need 15 minutes of vigorous cycling, or competitive soccer or basketball.
[1] e.g. an hour's dog-walking or golf are roughly equivalent to a 16 fl.oz can of Coca-Cola and a 2 oz packet of skittles, respectively.
The guy's reasoning was: You exercise for an hour doing something like walking or golf, then reward yourself with a snack? Net intake of calories [1]. And it's easier to cut a snack from your diet than to find the time and motivation to do an hour's exercise.
To put it another way, when you're obese exercising is like a job that pays ten cents an hour.
Of course, once you've become thin and athletic, you gain access to more time-efficient types of exercise. But that snack might still need 15 minutes of vigorous cycling, or competitive soccer or basketball.
[1] e.g. an hour's dog-walking or golf are roughly equivalent to a 16 fl.oz can of Coca-Cola and a 2 oz packet of skittles, respectively.