Each body type or combination of body types will have a different reaction to various macronutrient ratios. If you're not sure which type you are—or how to even begin thinking about your macros—here are the ISSA recommendations:
Ectomorph: If you're an ectomorph, you're naturally thin with skinny limbs and a high tolerance for carbohydrates. Usually, your metabolic rate is fast. A good starting macronutrient ratio for you would be something like 25% protein, 55% carbs and 20% fat.
Mesomorph: Mesomorphs are naturally muscular and athletic. They have a moderate carbohydrate tolerance and a moderate metabolic rate. Mesomorphs can usually start at a 30% protein, 40% carb, 30% fat macronutrient ratio.
Endomorph: If you're naturally broad and thick, you're probably an endomorph. Endomorphs have a low carbohydrate tolerance and a slow metabolic rate. If you're an endomorph, try a ratio of 35% protein, 25% carbs and 40% fat.