[Gudronich]

The end result of aerobics is higer "aerobic capacity" - meaning you can exercise harder and longer and burn more calories while exercising. (It has other health benefits too, but I'm speaking from a weight loss perspective only). But if you don't exercise, all the aerobic capacity in the world won't burn any calories. In fact, aerobics makes your body more efficient so that everyday tasks don't require as much energy as they do for less conditioned people.

Weight lifting is different. Although it's good exerciese, it doesn't burn anywhere near the calories that aerobic exercise does. However, the muscle you build (if you maintain it) will burn calories each and every day of your life.

If you gain just 1 pound of muscle and keep it for one year, that pound will burn about 15,000 calories (over 4 pounds of pure fat). 5 pounds of muscle will burn 8.5 pounds of fat, and 10 pounds of muscle will burn 17 pounds of fat - each and every year you have it. Think of the extra calories you can have in your diet and not gain weight with some muscle working for you!

And consider that as you diet and lose weight, 25% or more of the weight loss comes from muscle. (Atkins has some evidence that ketosis reduces this effect, which is one of the things that lead me to try it). The faster you lose, the higher the % of muscle loss. So if you don't do some type of muscle building exercise, you are actually losing your body's ability to burn calories (some might call this lowering your metabolism).

Aerobics is a good weight loss technique, and lifting a good weight maintenance technique. Doing both provides the best of both worlds.

[Now help me get motivated to do more aerobics - because although I did a solid hour at the gym today, I'm staring at my exercise bike and trying to think up a good excuse to skip it! ]