Macros: how to split protein, carbs and fat
No magic ratio: here's the simple method to calculate your macro split by goal, starting from calories and protein. Evidence-based.
Key takeaways
- Macros = protein (4 kcal/g), carbs (4 kcal/g), fat (9 kcal/g). Together they make your calories.
- There's no universal ratio: you build the split in order calories → protein → fat → carbs.
- For body composition, protein first, the rest adjusts to your preferences.
- Carbs vs fat: at equal calories and protein, little difference for fat loss.
“What's the best macro ratio: 40/40/20? 50/30/20?” Wrong question. There's no magic split that works for everyone. But there is a simple, logical method to build yours, starting from your calorie goal. Here's how, step by step.
What macros actually are
Macronutrients are the three families of nutrients that provide energy: protein and carbs give 4 kcal per gram, fat 9 kcal per gram (alcohol, for its part, gives 7). Your total calories are just the sum of your macros. Tracking macros means tracking calories with the detail of their composition, which lets you steer both weight and the quality of the result (muscle vs fat).
The 4-step method
- Set your calories. Start from your maintenance (TDEE), then subtract ~15–20 % to lose fat, or add ~10 % to build muscle.
- Set protein. Aim for 1.6–2.2 g/kg of bodyweight (the pillar of body composition).
- Set fat. Keep a minimum of about 0.8–1 g/kg (essential for hormones), then adjust to taste.
- Carbs = the rest. Convert remaining calories into carbs (÷4). They fuel energy and performance.
| Macro | Calculation | Amount |
|---|---|---|
| Protein | 2 g/kg × 70 = 140 g | 140 g (560 kcal) |
| Fat | ~0.9 g/kg × 70 ≈ 65 g | 65 g (585 kcal) |
| Carbs | rest: 855 kcal ÷ 4 | ~214 g |
Carbs or fat: which to favour?
This is where debates flare up. The reality, established by several controlled studies: at equal calories and protein, the carb/fat split changes little for fat loss (Hall et al., 2015; Aragon et al., ISSN 2017). In other words, choose the split you can stick to best: if you love bread and starches, lean toward more carbs; if you prefer fatty, satiating foods, raise fat. The best split is the one you can sustain.
The “miracle ratio” trap
Keto, very high-carb, 30/30/40… no ratio is magic in itself. What works is respecting calories and protein. The rest is preference and sustainability.
What about food quality?
Counting macros doesn't mean eating anything as long as “it fits.” At equal macros, minimally processed foods (whole grains, fruit, vegetables, lean protein, healthy fats) provide more fibre, micronutrients and satiety than ultra-processed products. Aim for about 80 % quality foods and leave room for enjoyment: that's what makes the approach sustainable.
Once your split is set, daily life is about hitting your three numbers. That's where tracking that automatically computes your macros (by scan or food search) saves a huge amount of time versus manual calculation.
Frequently asked questions
Do you need to hit your macros to the gram?
No. Aim for a ±5–10 g margin per macro. Weekly consistency matters more than per-meal perfection. Protein is the macro not to under-shoot.
Do fibres count in carbs?
Fibre is a carbohydrate that's poorly or not absorbed. Many apps count it in total carbs; the key is getting enough (25–30 g/day) for satiety and digestion.
Can you vary your split by day?
Yes, some put more carbs on training days. As long as the week's total calories and protein are respected, it's a valid option.
Scientific sources
- 1.Aragon AA, et al. ISSN position stand: Diets and body composition. J Int Soc Sports Nutr. 2017.
- 2.Hall KD, et al. Calorie for calorie, dietary fat restriction results in more body fat loss than carbohydrate restriction. Cell Metab. 2015.
- 3.Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation. J Int Soc Sports Nutr. 2014.
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