Activity Threshold

Here and there, I've read pieces that talk about how many calories of exercise would be needed to burn off a specific food.  For example, an article may say you need to walk 4 miles just to burn off the calories in a Big Mac.  This type of view incorrectly suggests that diet is the engine behind weight management, and that exercise is ineffective.

Two facts poke holes in this theory.  The first is that food intake balances out over the course of a week.  A splurge one day naturally leads to less eating the next day or two.  This is mostly an unconscious process, as the body attempts to regulate total food intake.

The second fact is that, over the course of a week, activity needs to pass a certain threshold for one to lose weight.  If you pass this threshold and eat a halfway decent diet, you will lose weight.  If you don't, nothing will happen.  A piece of cheesecake or some other indulgence won't alter this process.  People worry about eating too much, but many heavy exercisers eat more than the average couch potato.  The key to weight loss is energy expenditure - not counting every calorie you eat.