Dear The hulk-ette,

You're partially right. Muscle does weigh more than fat. When people incorporate a lot of weight training into their fitness program, it could make their muscles get bigger which could make the number on the scale increase.

Of course, this all depends on the type of strenuous exercise you're doing. If you're body building (lifting heavy weights as many times as you can) and if you're trying to bulk up, then you'll be more likely to increase your muscle mass which would increase your overall weight. Remember that your weight also depends on what you eat and if you're doing other exercise as well. For example, if you're also doing lots of cardio (which burns more calories than weight lifting exercise does), then you may ultimately lose more weight from this activity than the muscle weight you've gained from your weight training exercise.

If you're just trying to tone up by doing lots of repetitions of small amounts of weight, then you aren't likely add too much muscle mass. In this case, your weight may increase slightly, but you'll probably look and feel better in your clothes.

If your strenuous exercise is running marathons (or doing extensive amounts of other cardio exercises), then your unlikely to see big, bulky additions to your muscle mass. Just look at marathon runners! They're very lean and they tend not to have bulky muscles. Also, doing large amounts of cardio exercise burns more calories, so you'll likely burn a lot more fat compared to the amount of muscle that you'd build, and your overall weight may decrease.

However, let's get back to the first part of your question. It is a myth that fat cells can change into muscle. Body fat and muscle are two completely different types of cells in the body. You can burn fat and build muscle, but a fat cell will never turn into a muscle cell. Body fat is a storage place where our body puts extra energy when we eat more calories per day than we need. If someone continues to consume more calories than s/he needs, the body can create new fat cells to store the extra energy. When we "burn fat" we are actually shrinking the size of our fat cells by using the energy that has been stored there. On the other hand, we have only a fixed number of muscle cells so when we are building muscle the individual muscle cells are increasing in size (bulking up).

Hopefully, this information was both clarifying and interesting. You can always talk with a Registered Dietitian (RD) or a trainer to help determine the weight and exercise plan that's right for you. At Columbia, nutrition appointments are available by logging in to Open Communicator or by calling 212-854-2284, and personal trainers are available at Dodge Fitness Center. If you are not a student at Columbia, check with your local gym or health care provider for nutrition and exercise referrals.

Have fun with your exercise plan and enjoy the many healthful benefits.

Alice

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