KNOW YOUR BODY TYPE, BEFORE STARTING TO ALTER IT

ECTOMORPHS

Are long and lean, with little body fat, and little muscle. They have a hard time gaining weight. Fashion models and basketball players fit this category. While most of us love to hate these genetically-blessed individuals, some male ectomorphs may not be thrilled with their narrow-chested frames, and some female ectomorphs long for more womanly curves.

MESOMORPHS

 Are athletic, solid, and strong. "They're not overweight and not underweight," says Colby, "and they can eat what they want without worrying too much about it." They both gain and lose weight without too much effort.

ENDOMORPHS

On the other hand, have lots of body fat, lots of muscle, and gain weight easily. "Football lineman tend to be endomorphs -- they're heavier and rounder individuals," says Colby. "And they don't have to necessarily be overweight. Both Oprah Winfrey and Marilyn Monroe are classic examples of endomorphs.