Myth: Aerobic exercise is all the exercise you need to effectively control your weight.

Fact: A review of the available data strongly indicates that, in general, combining a conventional aerobic exercise program with a calorically restricted diet does little (IF ANYTHING) to help you preserve lean body mass during your weight-reduction efforts. It is important to keep in mind that the lower your lean body mass is, the lower your resting metabolic rate (i.e., the calories expended by the body to maintain life and normal bodily functions such as respiration and circulation) will be. As a result, it is more likely that you will regain some or all of the weight you lost. On the other hand, if you engage in an exercise program that is designed to improve your level of muscular fitness and weight loss, you enhance the likelihood that you will be able to maintain your level of lean body mass. Accordingly, the optimal exercise prescription for sound weight management is one that combines aerobic conditioning and strength training. Such a prescription will allow you to expend a relatively large number of calories, while simultaneously preserving or increasing your level of lean body mass.

International Sports Sciences Association (ISSA) 8th Edition Text