What Are Macros?
Macronutrients (macros) are the three primary nutrients your body uses for energy: protein (4 cal/g), carbohydrates (4 cal/g), and fat (9 cal/g). The right macro split depends on your goal, body type, and activity level.
Macro Splits by Goal
| Goal | Protein | Carbs | Fat | Calorie Adjustment |
|---|---|---|---|---|
| Weight Loss | 35–40% | 30–35% | 25–30% | −300 to −500 cal/day |
| Maintenance | 25–30% | 40–50% | 25–30% | TDEE (no change) |
| Muscle Gain | 30–35% | 40–50% | 20–25% | +200 to +400 cal/day |
| Keto | 25–30% | 5–10% | 60–70% | Varies |
Protein Needs Explained
Protein is the most important macro for preserving and building muscle. General evidence-based guidelines:
- General population: 0.7–1.0g per kg of body weight per day
- Active adults / fitness enthusiasts: 1.4–2.0g per kg
- Strength athletes / muscle building: 1.6–2.2g per kg
- Weight loss (preserving muscle): 2.0–2.4g per kg
Frequently Asked Questions
What is IIFYM?
IIFYM stands for "If It Fits Your Macros" — a flexible dieting approach where you can eat any food as long as it fits within your daily macro targets. It focuses on overall nutrition numbers rather than restricting specific foods.
Should I count net carbs or total carbs?
For general fitness goals, total carbs works well. For keto or low-carb diets, net carbs (total carbs minus fiber) is commonly used, as fiber is not absorbed and doesn't impact blood sugar significantly.
How many grams of protein do I need to build muscle?
Research suggests 1.6–2.2g of protein per kg of body weight per day is optimal for muscle protein synthesis when combined with resistance training. Beyond ~2.2g/kg, additional protein shows minimal extra benefit.
Is fat bad for you?
No — dietary fat is essential for hormone production, brain health, and absorption of fat-soluble vitamins (A, D, E, K). The key is the type: focus on unsaturated fats (olive oil, avocado, nuts) and limit trans fats and excessive saturated fats.
How accurate is this calculator?
This calculator uses the Mifflin-St Jeor equation for BMR and standard TDEE activity multipliers, which are well-validated. Individual results vary — treat the output as a starting point and adjust based on real-world results over 2–3 weeks.