During the TV show the Biggest Loser the 14 participants lost a ridiculous amount of weight (average weight loss 128 pounds) over a 30 week period, which is approximately 4 pounds per week. When we convert this into calories this would be 14,000 calories per week. To be clear every participant did not lose 4 pounds per week, this was the average weight loss among all of the participants. However when eliminating this many calories in a short period of time the body detects that it’s undergoing starvation and ‘a famine’ must be occurring. The participant’s stress hormone goes into overdrive, the body becomes more efficient at conserving energy and the risk of losing lean body mass is high. Utilization of unnecessary tissue for energy when energy intake is extremely low increases the risk of losing muscle. The participants experienced a significant amount of weight lost over a short period of time which causes the body to reduce its lean body mass. Numerous studies have demonstrated that resistance training can increase lean muscle mass in both men and women and help boost the Resting Metabolic Rate (RMR). By trying to maintain as much of the lean body mass (LBM) with heavy resistance training, an individual can limit the amount of decreases in the RMR that accompany caloric restricted diets.
Meta-analyses of weight loss programs have shown that diet plus exercise is a more effective approach than diet alone or exercise alone. Typically with weight loss diets that are performed without exercise, the composition of the weight loss is approximately 69% fat and 31% lean body mass (LBM), so if you lose 20 lbs., approximately 14 lbs. of the loss is fat and 6 lbs. is LBM. When aerobic exercise is performed in conjunction with a weight loss diet 78% of the weight loss is loss of fat mass and 22% is from LBM. During a weight loss diet performed with both aerobic exercise and heavy resistance training the loss of body fat is approximately 97% and 3% LBM. Interestingly the average percent fat mass (FM) loss by the participants in the Biggest Loser was approximately 80% while the LBM lose by the participants was approximately 20%. By limiting the loss of lean body mass and subsequently a reduction in the RMR, the amount of calories expended will better be maintained. In essence resistance training encourages the body to gain or at least maintain muscle and burn fat, during a weight loss program. This positive change in body composition will increase the body’s ability to maintain a certain weight once weight loss goals are achieved.
A goal should be to progressively increase the amount of resistance used during weight training, as this is the best way to hold muscle during weight loss diets. After a thorough warm-up, make sure that you use progressively heavier weights, working large muscle groups with compound movements for 10-12 repetitions. Resistance exercises like the leg press/squat, row, lat pull-down, hip and back extension/dead-lift, resistive abdominal crunches and chest press/bench press are exercises that work large muscle groups and are more affective in facilitating muscle growth.