Q: I gained in the last 3 months 5 pounds of lean body mass and lost 10 pounds of fat. in those 3 months I always burned more calories than I ate. But I thought to gain lean body mass one has to eat more than what one burns,so hoe come I gained muscle? The theory that one cannot lose fat and gain muscle at the same time may not be true.

A: Big CONGRATS to you on your success! It is certainly possible to lose fat and to gain muscle at the same time, but in order to do that consitently and significantly at least one of several things have to be true:

• You are in your teens or early 20s. This is the prime age, especially for men, and your body is at its peak and at the highest point of natural testesterone production which promotes fat loss and muscle gain.
• You are a relative beginner when it comes to weightlifting (under a year of consistent exercise) and/or your body composition has relatively high fat levels (more than 15% for men, more than 25% for women). Changing body composition is a process of diminishing returns. Initial progress is fast, but continuing the progress and getting to the six-pack stage is not easy or even possible for some people. Once they get past the first year or so of training, most people will no longer be able to gain muscle while losing fat at significant pace.
• You have superior genetics. Some people are just born lucky. These are the people who are natural mesomorphs (large, musclar body types) or natural ecto-mesomorphs (lean, athletic body types). These people in general have relatively easy time putting on muscle and burning fat.
• You supplement with anabolic steroids. If you are willing to go this far and you're sufficiently educated about steroid use, you will be able to achieve body development far past what is possible naturally. I do not advocate the use of anabolic steroids and strongly advise anyone considering them to first educate themselves on the proper use and the risks that go along with such use.