What type of exercise do you think will burn off the most fat for you? Aerobics many people say, weight training others will say. But would you believe neither?

In a recent book written by Dr. Al Sears, he relates the outcome achieved when he had twin girls follow different exercise routines while he measured the change in their weight, Body Mass Index, body fat, and muscle mass for 4 months.

Twin A used a graduated program of aerobic jogging and worked up from one mile a day to 10 miles daily for her exercise. How much weight and how much fat would you guess she lost in 4 months?

Twin B used Dr. Sears' PACE© system, in which she used a graduated program of running in short bursts of increasing intensity with short periods of recovery in between each sprint. At the end of the 4 months Twin B was sprinting 50 yards followed by a recovery period of 30 seconds and repeating for a total of 6 sets. This was certainly a shorter time than Twin A was spending to jog 10 miles every day.

Both twins started with 24.5% body fat. At the end of 4 months, Twin A had lost 8 pounds of fat and 2 pounds of muscle. Her body fat dropped to 19.5%.

Twin B, using Dr. Sears' PACE© system, had dropped 18 pounds of fat, built 9 pounds of muscle and had a very healthy body fat of 10%.

So Twin A lost 10 pounds but lost muscle, and Twin B lost more fat and built muscle.

Which "twin" would you rather follow?