Below are the 3 major classifications of body types. However, they really don’t tell the whole story as it relates to bodybuilding genetics.

Body type groups:

Ectomorph: These are the traditional “skinny hardgainers” of bodybuilding. They have a fast metabolism and low bodyfat %. Gaining weight can be difficult when they are younger. When their metabolism slows as they get older, is when weight gain becomes easier. “Skinny fat” is a term for ectomorphs who are out of shape and have a gut.

Mesomorph: Mesomorphs have a balanced athletic body. They don’t have much of a problem gaining or losing weight. Only later in life, when their metabolism slows, gaining fat is more of a problem.

Endomorph: Endormorphs gain weight very easily. As a result, they naturally tend to carry a high bodyfat %. Lack of excercise and dieting can easily cause them to become obese.

What the classifications don’t tell you:

Each individual of a bodytype will have different genetics from each other of the same bodytype, when it comes to muscle building and fat loss abilities. Some ectomorphs for example, will have a much easier time gaining muscle than other ectomorphs. Some ectomorphs might have more of a tendency to put on fat instead of muscle compared to most ectomorphs.

Where people gain the weight, also varies slightly for each person. Some might gain mostly fat on their stomach. Others of the same bodytype might gain weight, but it’s more evenly distrubuted across their body in the form of both fat and muscle.