The right diet to achieve optimal results in muscle building depends strongly on the type of your body. There are three main body types:
Ectomorphological (Hardgainer): The body structure is characterized by long limbs, low body fat and slow weight gain.
Endomorph (Softgainer): Rather round body structure, with a tendency to accumulate fat quickly at the waist, hips and thighs. Women often have wide hips. Slow metabolism, but rapid build-up of muscle and fat mass.
Mesomorph: Sporty body, with broad shoulders, strong arms and legs and a narrow waist. The proportion of muscle mass is high and therefore usually very athletic. Fast and good results in muscle building.
Body types differ mainly in their muscle mass, the tendency to fat accumulation and the general structure. However, many people cannot be classified into a certain type, but are rather "mixtures" of different types.