William H. Sheldon, PhD, MD, introduced the concept of body types, or somatotypes, in the 1940s. Since then, nutritionists, exercise physiologists, and even doctors have used it to help design effective, individualized fitness plans. The gist is that everyone falls, though not altogether neatly, into the three categories below. Keep in mind that these are generalizations, and that most of us have characteristics of two or even all three somatotypes.
People are born with an inherited body type based on skeletal frame and body composition. Most people are unique combinations of the three body types: ectomorph, mesomorph, and endomorph.
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.
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.”
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.