Weight Training & Getting Lean

"Losing Fat and Gaining Muscle"

- By William J. Kraemer, Steven J. Fleck

Q: I’m interested in losing fat and gaining muscle. What is the basis of a conditioning program to achieve these goals? How can one get lean and build muscle if caloric expenditure is not that high?

A: The ability of resistance training to increase fat-free mass (e.g., muscle) appears to be the primary factor mediating changes in body composition (reducing fatness), as opposed to the direct energy costs of resistance exercise. Therefore, to achieve reductions in body fat, resistance-training programs should include a preponderance of multiple-joint, larger muscle group exercises. Such exercises, like the squat, deadlift, bench press and row, incorporate several large muscle groups. The potential for gains in fat-free mass theoretically would be greater following resistance-training programs that incorporate multiple-joint resistance exercises for the total body with additional single-joint, isolation-type resistance exercises for target areas.

In addition to increased energy expenditure, an important adaptation to endurance training involves changes in lipolytic (fat burning) activity. Lipolysis refers to processes that break down stored fat (adipose tissue) in the body. One study reported that cycle ergometer exercise performed 30 to 45 minutes per day, four days per week, for three months elicited significant reductions in fat mass with concomitant enhancement of lipolysis in obese men. Specifically, the fat burning activities of certain catecholamines (e.g., epinephrine) were increased, while the anti-lipolytic effects of other agents (e.g., insulin) were reduced. Thus, endurance training may enhance the availability of adipose tissue for use as an energy substrate and thereby aid in body fat reduction.