There are three general body types (somatotypes), ectomorph, mesomorph, and endomorph.
Most people don't fall 100% into one category especially if they've already participated in years of training. For example, an ectomorph can have more mesomorphic characteristics after years of training in a resistance program.
However, each somatotype has distinct physiological characteristics that can be linked to metabolic differences. Figuring out your body type can help you adjust your nutrition to meet your goals and improve your body composition.
Here are some very general guidelines based on somatotypes:
Ectomorph: Thin individuals with smaller bone structures. They generally have an "I" shape, high metabolic rate and carb tolerance. A macro distribution may be, 55% carbs, 25% protein, 20% fat.
Mesomorph: These individuals have "athletic," V-shaped bodies with medium bone structures. They tend to be testosterone and growth hormone dominant which leads to more muscle mass and lower body fat percentage. A macro distribution may be 40% carb, 30% protein, and 30% fat.
Endomorph: These individuals have higher body mass, fat, and larger bone structures. Endomorphs are typically less active and tend to store excess calories more as fat than burn them off through constant movement. For endomorphs, carbohydrates should be more controlled and timed adequately with their eating. A macro distribution may be 25% carb, 35% protein, and 40% fat.