Fit Nutrition library
Macro Calculator
Explore a macronutrient starting range.
How it’s calculated
Calories come from Mifflin–St Jeor resting energy × activity. The split then sets protein per kilogram, fat as a share of calories, and carbohydrate as the remainder.
Protein = 1.6 g × weight(kg) · Fat = 25% of calories ÷ 9 · Carbs = remaining calories ÷ 4.
Source: Mifflin–St Jeor (1990); protein range per ISSN position stand on protein and exercise.