Exercise Helps Keep Weight Off More Than It Helps You Lose It, Research Shows

Exercise is often added to calorie counting or portion control as a way to lose weight, but research shows it typically has only a modest direct effect on weight loss itself. Several processes help explain why: exercise can stimulate appetite and increase food intake, people often move less for the rest of the day after a workout, and the body becomes more efficient over time, burning fewer calories for the same activity, a process called metabolic adaptation.

Exercise appears to matter far more for keeping weight off than for losing it in the first place. In a study of more than 1,100 people, physical activity had little effect on how much weight participants initially lost, but higher levels of activity after weight loss were strongly linked to maintaining that loss. Exercise in the study was also linked to better cholesterol, lower inflammation, and better blood sugar control and insulin sensitivity. Evidence also suggests that combining exercise with weight-loss drugs such as Saxenda may help people maintain weight loss better than using the drug alone.

Several mechanisms may explain why exercise helps with maintenance more than initial loss. Losing weight lowers resting energy expenditure, the calories the body burns while doing nothing, by more than would be expected from the weight lost alone, which is thought to contribute to weight regain; exercise raises total daily energy expenditure, partly offsetting this drop. Weight loss also typically reduces muscle mass along with fat, which further lowers resting energy expenditure, but exercise, especially resistance training such as lifting weights, can help preserve or rebuild muscle.

Exercise also helps the body maintain its ability to burn fat, which typically becomes less efficient after weight loss, and it improves insulin sensitivity, reducing the amount of insulin needed to regulate blood sugar; higher insulin levels can promote fat storage and reduce fat breakdown. Aerobic exercise such as brisk walking, cycling or running burns calories and, at higher intensities, may enhance fat-burning, while resistance training helps build and preserve muscle mass that supports a higher resting energy expenditure.