21.   Because body fat cannot appear out of thin air, the explanation for our increasing weight must be that we are using significantly fewer of the calories we consume.

22.   Because muscle weighs more than fat, knowing your percentage of body fat helps you monitor your total health and weight loss.

23.   Because muscle is heavier than fat, Baker can carry a few extra pounds as long as his body fat is reasonably low.

24.   Because adolescence is the time that young women begin to get more body fat, these exercise patterns contribute greatly to their battles with unwanted weight gain.

25.   Ben Johnson, a professor at Georgia State University, who runs the institute, sits in the Body Pod, a computerized device that measures body fat.

26.   Both body fat and inactivity can increase blood levels of estrogen.

27.   Both have limits on body fat, with wrestlers not allowed to drop below seven percent.

28.   A rigorous off-season workout regime helped McGwire reduce his body fat.

29.   A person who is very muscular but who has a low percentage of body fat could end up with the same BMI as someone who is truly fat.

30.   A trained acrobat who exercised religiously until the end of his life, Westermann lacked anything remotely resembling body fat.