What are macros?
Macronutrients (“macros”) are the three nutrients that provide calories: protein, carbohydrate and fat. Each has a different job. Protein builds and repairs muscle, skin and hormones; carbohydrates are your body’s and brain’s main fuel; and fat supports hormone production, brain health and the absorption of vitamins A, D, E and K. Counting macros — sometimes called IIFYM (“if it fits your macros”) — helps you eat the right balance, not just the right number of calories.
How the macro calculator works
The calculator first works out your daily calorie target from your BMR (Mifflin-St Jeor equation), activity level and goal — or uses the number you enter. It then splits those calories by your chosen percentages and converts them to grams using these energy values:
- Protein: 4 kcal per gram
- Carbohydrate: 4 kcal per gram
- Fat: 9 kcal per gram
Example: 1,800 kcal on a balanced split (25/50/25) = 1,800 × 0.25 ÷ 4 = 113 g protein, 1,800 × 0.50 ÷ 4 = 225 g carbs and 1,800 × 0.25 ÷ 9 = 50 g fat.
Healthy macro ranges: low, normal and high
International guidelines (the Acceptable Macronutrient Distribution Ranges, AMDR) suggest these ranges for adults:
| Macro | Low | Healthy range (AMDR) | High |
|---|---|---|---|
| Protein | Under 10% of calories (or under 0.8 g/kg) | 10 – 35% of calories | Over 35% — usually unnecessary; take care with kidney disease |
| Carbohydrate | Under 45% (low-carb); under 10% (keto) | 45 – 65% of calories | Over 65%, especially from sugar and white flour |
| Fat | Under 20% — may affect hormones and vitamin absorption | 20 – 35% of calories | Over 35% (except planned keto); keep saturated fat under 10% |
Which macro split should I choose?
- Balanced: best for most people and families; easy with roti, rice, dal, vegetables and lean protein.
- High protein: helps you feel full and protects muscle while losing weight.
- Lower carb: can help with insulin resistance, PCOS and type 2 diabetes — choose high-fibre carbs.
- Keto: very low carb; only with professional guidance.
Benefits of tracking macros
- Better body composition: enough protein helps you lose fat, not muscle.
- Steadier energy and blood sugar by spreading carbs and protein through the day.
- More flexibility than strict meal plans — you can include favourite foods in the right portions.
- Improved performance for training, sport and recovery.
Health warnings
- People with kidney disease should not follow a high-protein diet without medical advice.
- Anyone taking insulin or diabetes tablets must speak to their doctor before cutting carbs — there is a risk of low blood sugar.
- Keto and very low-fat diets are not recommended in pregnancy, breastfeeding or for teenagers.
- Food quality still matters: 50 g of carbs from lentils and vegetables is very different from 50 g from sweets.
- If tracking food becomes stressful or obsessive, take a break and seek support.
Putting your macros on the plate
A simple way to hit your numbers without weighing everything: fill half your plate with vegetables, a quarter with protein (a palm-sized portion of chicken, fish, eggs, tofu or a cup of dal) and a quarter with wholegrains such as brown rice, quinoa or a whole-wheat roti, plus a thumb of healthy fat like olive oil or nuts. The recipe nutrition calculator shows the macros in your home-cooked meals.
Frequently asked questions
What is the best macro ratio for weight loss?
There is no single best ratio. Most people lose weight well with higher protein (25–35% of calories), moderate carbs from high-fibre foods and 25–35% fat, as long as total calories are below their TDEE.
How many grams of protein, carbs and fat should I eat?
It depends on your calorie target. On 1,800 kcal with a balanced split you would eat about 113 g protein, 225 g carbohydrate and 50 g fat. Use the calculator above for your personal numbers.
Do I need to count macros to lose weight?
No. Calories matter most for weight loss, but counting macros can help you feel fuller, keep muscle and improve food choices. Many people track for a few weeks to learn portions and then stop.
Are macros the same for women and men?
The percentages can be the same, but men usually need more calories, so their gram targets are higher. Pregnant and breastfeeding women have higher protein needs.
Is a keto macro split healthy?
Keto can help some people lose weight or manage blood sugar short term, but it is very restrictive and low in fibre. It is not suitable for everyone, so get medical or dietitian advice first.
Sources
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids (AMDR). 2005.
- WHO. Healthy diet fact sheet.
- Mifflin MD, St Jeor ST, et al. Am J Clin Nutr 1990.