Mesomorph, Ectomorph, Endomorph Simplified

by Dr. Eric Berg DC


In the 1940s, an American psychologist William Herbert Sheldon came up with a theory of relating body types with human emotion. The term somato comes from the Latin work for body. Somatotypes means body types.

Sheldon proposed that the human physique be classified according to the relative contribution of three germ layers of embryonic development: the endoderm (develops into the digestive tract), the mesoderm (becomes muscle, heart and blood vessels), and the ectoderm (forms the skin and nervous system):

• Ectomorphic: long and thin muscles/limbs and low fat storage; usually referred to as slim.    Ectomorphs are not predisposed to store fat or build muscle.

• Mesomorphic: medium bones, solid torso, low fat levels, wide shoulders with a narrow waist; usually referred to as muscular. Mesomorphs are predisposed to build muscle but not store fat.

•Endomorphic: increased fat storage, a wide waist and a large bone structure, usually referred to as fat. Endomorphs are predisposed to storing fat.

These arbitrary classifications are far from being scientific. To base a body type based on an embryonic organ development is a stretch. Your body type is developed through hormones. Hormones are the guiding messages the body gives to create shape and size. A dwarf or giant stems from shifts in hormones. Fat accumulation occurs from hormones.

Let’s take a female with excessive hips and thighs. Estrogen’s function is to protect the fetus by providing excess fat around the lower stomach and thighs. If a female becomes estrogen dominant, she most likely will develop large thighs and hips.

On the other hand, a person with a sagging stomach is suffering with excess cortisol, that stress hormone that stores fat around the vital organs, which happen to be in your midsection.

Then you have people who are large all over equally. The thyroid gland controls and coordinates all the cells in the body. Thyroid body types hold weight all over equally. So when they gain weight, it’s in the neck, upper part, lower part, belly – everywhere.

Theoretically there are only two body types, but if the liver is damaged it will leak fluid, not fat, into the abdomen, giving a pot-belly appearance. The entire body looks fine except for the protruding belly. The stomach is filled with fluid from damage to the liver, not hormonally.

The four body type theory of weight gain is much more credible in terms of describing the relationship between shape and hormones.