How Much Exercise to Maintain Weight Loss?

• Ask Dr. Tim Church

I read on the government's My Pyramid site that to lose weight, I need about 60 minutes of exercise per day, but to maintain weight loss, I need even more — 60 to 90 minutes per day. That's a lot! Why would I need more exercise to maintain weight I've already lost than to lose weight? 

— Kelly, Wash.

The bottom line is that losing weight is not nearly as difficult as keeping it off — and one common characteristic of individuals who maintain weight loss is regular physical activity. Here’s a quick Metabolism 101 lesson: The number of calories you burn each day (not counting those from exercise) is primarily determined by how big or small you are. Muscle and fat burn calories just by existing. The bigger you are, the more muscle and fat you have, which will burn more calories throughout the day. As you lose weight, there is less of you, and thus you burn fewer calories in general, so exercise becomes very important in helping you keep the weight off.

Given the numerous conflicting recommendations that are made for the amount of exercise that's necessary to lose weight, people understandably become frustrated. To simplify, I recommend exercising at least 45 to 60 minutes per day — both for weight loss and to keep the weight off.