by Deborah L. Mullen, CSCS

Why Diets Don't Work
If you go "on a diet", what does that mean? That you will eventually go "off the diet". If you haven't changed your eating and physical activity behaviors, what's going to happen? Rationally, you know the answer, but emotionally, you engage in wishful thinking, hoping that this time you will lose the weight and keep it off. What weight are we talking about? When people tell me they lost 12 pounds in two weeks, I ask "12 pounds of what?" On low-calorie diets, about 25 percent of the weight loss may be muscle (Ballor & Polehlman 1994).

Losing muscle is a bad thing. Muscle tissue is very active--it burns a lot of calories. Every pound of muscle burns about 35 calories per day, just staying alive. Using the above example, if you lost 12 pounds, then, you lost three pounds of muscle. You would be burning 105 less calories per day or 3150 per month. Since there are 3500 calories in a pound of fat, you would gain almost one pound of fat per month just from the muscle mass that you lost!

Why The Middle-Aged Spread Keeps Spreading
Inactive adults lose around one-half pound of muscle per year, or five pounds per decade. Since most people continue to eat as much as usual, what's going to happen? If you take in more calories then you burn, the extra calories get stored as fat. Fat is less dense then muscle---a pound of fat takes up more room than a pound of muscle. This means that as you lose muscle and gain fat, your weight might remain the same over the years, but your waistline will continue to expand!

Rev Up Your Metabolism--The Key to Permanent Weight Loss
How can we lose and keep off extra fat? You need to increase your resting metabolic rate (RMR), which is the pace your body burns calories at rest. Your RMR is closely linked to the amount of muscle you have--remember, muscle burns more calories than fat. Adding muscle will raise your RMR and will greatly increase the chance that the weight loss (more accurately fat loss) will be maintained.

Strength Training Versus Aerobic Exercise
Contrary to what many people think, strength training is as important, maybe more important to successful fat loss than aerobic exercise. The reason lies in the amount of calories that are burned when you aren't exercising. Depending on the intensity and your weight, an aerobic workout (walking, cycling, stairstepping) will burn approximately 300 calories per hour. If the exercise is strenuous enough (which is unlikely in the beginning exerciser) the RMR will be elevated temporarily up to a few hours afterwards. Compare this to strength training which elevates the RMR permanently. The RMR accounts for 60 to 75 percent of your daily calorie expenditure, so even a modest increase will help burn off more fat.

One study (Campbell 1994) found that a three-month basic strength-training program resulted in the subjects gaining three pound of muscle and losing four pounds of fat, while eating 370 more calories per day (a 15 percent calorie increase). Remember, aerobic exercise generally doesn't increase muscle tissue. In fact, excessive amount of aerobic exercise combined with a low-calorie diet can cause the loss of some muscle tissue. This is not to say that overweight individuals shouldn't do aerobic exercise--it offers many health benefits and is a part of a weight loss program. It's just that aerobic exercise by itself may not be the best solution for permanent weight (fat) loss.

Don't think that you need to workout in a gym for two hours to strength train. Significant gains can be made with a consistent 30-minute workout performed 2 -3 times per week. This could be your key to successful weight control!