How Important Is Exercise Versus Just Calorie Intake?

Exercise and calorie intake play different roles in weight loss, weight maintenance and weight gain, but both are important for healthy weight management. The U.S. Department of Health and Human Services recommends adults participate in 2.5 to 5 hours of moderate aerobic exercise each week and muscle strengthening exercises at least two times each week. Your calorie needs depend on your age, gender and activity level. Your weight management expectations determine if you should focus more on exercise or calorie intake to achieve your goals.

  1. Weight Loss

    • Your calorie intake determines your weight loss success, but exercise can enhance weight loss and decrease body fat. A study published in 2007 in the “Journal of the American Dietetic Association” reports that although subjects who reduced their calorie intake lost 5 to 9 percent of their body weight over the course of six months, subjects who exercised without calorie restriction experienced minimal weight loss. A review published in 2009 in “Medicine and Science in Sports and Exercise” reports exercising more than four hours per week can enhance your weight loss, and strength training, specifically, increases muscle mass and reduces body fat. However, if you increase your physical activity but also eat more, you may not lose weight.

    Weight Maintenance

    • Exercise plays the most important role in maintaining a weight loss and preventing weight gain. The 2009 review published in “Medicine and Science in Sports and Exercise” suggests that exercising 2.5 to 4 hours per week can help prevent weight gain, while exercising more than 4 hours each week can help maintain a weight loss long-term. However, calorie intake also plays a key role in healthy weight maintenance, since overeating causes weight gain regardless of your activity level.

    Weight Gain

    • Your calorie intake is the most significant determinant of successful weight gain, but exercise determines how much muscle mass you gain. Increasing your calorie intake without exercise will likely cause an increase in fat mass. Resistance training, such as weight lifting, is particularly useful when it comes to building muscle. The 2009 review published in “Medicine and Science in Sports and Exercise” reports that resistance training increases lean mass, helps decrease body fat and helps reduce your overall disease risks. The U.S. Department of Health and Human Services recommends participating in muscle-strengthening exercises that work all of your major muscle groups. These include your shoulders, biceps, triceps, chest, back, abdomen, glutes and leg muscles.

    Calorie Recommendations

    • Your calorie needs are based on your weight management goals. If you’re already at a healthy weight, you need 13 calories per pound if you’re sedentary, 15 calories per pound if you’re moderately active and 18 calories for each pound of body weight if you’re active, according to the University of Washington. If you’re overweight, reduce your current intake by 500 to 1,000 calories daily for a 1- to 2-pound weight loss per week, according to the National Heart, Lung and Blood Institute. If your goal is to build muscle mass and gain weight, increase your calories by 500 to 1,000 daily, according to the U.S. Anti-doping Agency.