What's the Best Macro Split?

There is no universal "best" macro split

Type "best macro ratio" into any search engine and you'll find confident, conflicting answers. 40/30/30. High protein, low carb. Keto. Carnivore. The truth is that no single macro split is optimal for every person and every goal — but there are well-established ranges that work well for different objectives.

Here's how to find the right starting point for yours.

Understanding macro ratios

A macro split expresses your calorie intake as a percentage coming from each macronutrient:

• Protein: 4 calories per gram

• Carbohydrates: 4 calories per gram

• Fat: 9 calories per gram

A 40/30/30 split means 40% of calories from carbs, 30% from protein, 30% from fat. It's a popular starting point, but not the best fit for everyone — particularly those with specific body composition goals.

Macro split for fat loss

During a fat loss phase, protein takes priority. Higher protein intake preserves muscle mass in a calorie deficit and keeps hunger under control. A typical fat loss macro split looks like:

• Protein: 30–40% of calories

• Carbohydrates: 30–45% of calories

• Fat: 20–30% of calories

In absolute terms for an 80 kg person eating 2,200 calories, this translates to roughly 165–220g protein, 165–247g carbs, and 49–73g fat.

Macro split for muscle gain

Building muscle requires adequate protein, generous carbohydrates to fuel training and recovery, and sufficient fat for hormone health. A typical muscle gain split looks like:

• Protein: 20–30% of calories

• Carbohydrates: 45–55% of calories

• Fat: 20–30% of calories

Note that the protein percentage is lower than in a fat loss phase — but in a calorie surplus, you're eating more food overall, so the absolute gram amount is still high.

Macro split for maintenance

Maintenance is about sustaining your current body composition while fuelling performance and health. The ranges are more flexible here:

• Protein: 25–35% of calories

• Carbohydrates: 35–50% of calories

• Fat: 20–35% of calories

Why grams matter more than percentages

Macro ratios are a useful communication tool, but they can be misleading. A person eating 1,500 calories and a person eating 3,000 calories might both follow a 30% protein split — but one is eating 112g of protein while the other gets 225g. These are very different nutritional pictures.

This is why the best approach is to set macros in grams based on your body weight and goals first, and let the percentage ratio be whatever it works out to be — rather than starting with a ratio and working backwards.

How to find your personal starting point

1. Calculate your TDEE (total daily energy expenditure)

2. Adjust for your goal (deficit for fat loss, surplus for muscle gain)

3. Set protein in grams: 1.6–2.4g × your body weight in kg

4. Set fat in grams: 0.8–1.2g × your body weight in kg

5. Fill remaining calories with carbohydrates

6. Track for three weeks, then adjust based on results

Macro M8 handles all of this automatically — enter your details and goals, and you'll have a personalised starting point in under two minutes.