Macro Calculator

Macronutrient distribution is the second-most-important nutritional variable after total energy balance. Each macronutrient plays distinct metabolic roles: **Protein (4 kcal/g)**: Building blocks for muscle, enzymes, hormones, and immune cells. Has the highest thermic effect of food (TEF = 20-30%), meaning 20-30% of protein calories are spent digesting it. Protein promotes satiety more than carbs or fat, making it especially valuable during calorie restriction. **Carbohydrates (4 kcal/g)**: The body's preferred fuel for high-intensity exercise, brain function, and red blood cells. Stored as glycogen in muscle (~400 g) and liver (~100 g). Excess carbohydrate is converted to fat through de novo lipogenesis, though this pathway is relatively inefficient. **Fat (9 kcal/g)**: Essential for hormone production (testosterone, estrogen), cell membrane integrity, fat-soluble vitamin absorption (A, D, E, K), and brain health. Minimum intake should not drop below 20% of calories to avoid hormonal disruption. **Common macro splits**: - Balanced (30/40/30): Good starting point for most people - High protein/muscle building (40/30/30): Maximizes muscle protein synthesis - Low carb (30/20/50): May improve insulin sensitivity in sedentary, insulin-resistant individuals - Endurance athlete (20/55/25): Prioritizes glycogen stores for long-duration exercise - Ketogenic (20/5/75): Very low carb, forces fat oxidation and ketone production The percentages must sum to 100%. If they don't, the calculator will produce results that don't match total calorie intake.