How do I work out my macros?
Your macros are your protein, carbs and fat. Set your calories first, then protein at about 1.8 to 2 g per kilo of body weight, fat at no less than 0.8 g per kilo, and give carbs the calories that are left. The calculator below does it for you, with the reason for every number.
By Simon, head coach at Zama Fitness. Updated 7 November 2026.
Macro calculator
Your macros, every day
1,610kcal a day
410 kcal below your burn of 2,020, so you lose fat.
Protects your muscle while you eat less.39% of calories
Fuels your training. Fills what is left.27% of calories
Hormones and recovery. Never below the minimum.35% of calories
Protein a meal
52 g
across three meals
Protein per kg
2.0 g
of body weight
Fat minimum
62 g
a day, 0.8 g per kg
- You burn about 2,020 kcal a day: your resting burn is 1,460, times 1.38 for a desk job and 3 training days a week.
- Fat loss: 403 kcal below your burn (20%, capped at 500) so you lose fat, not muscle.
- Protein is 2 g per kg of body weight.
- Fat is at least 0.8 g per kg or 25% of calories. Carbs fill the rest and fuel training.
These are your starting macros. As your weight and training change, the numbers have to move with them. Your coach sets them again every four weeks.
For adults aged 18 and over. If you are pregnant, have diabetes, kidney disease or another health condition, or take weight-loss medication, speak to your GP or prescriber before changing your diet.
What are macros?
Macros, short for macronutrients, are the three nutrients that give food its calories. Every calorie on a food label comes from one of them, plus alcohol if there is any.
Protein
- Calories per gram
- 4 kcal
- What it does
- Builds and keeps muscle, and fills you up
- Where you find it
- Meat, fish, eggs, yoghurt, skyr, cottage cheese, beans, lentils, tofu
Carbohydrate
- Calories per gram
- 4 kcal
- What it does
- Fuels training and everyday energy
- Where you find it
- Bread, rice, pasta, potatoes, oats, fruit, vegetables
Fat
- Calories per gram
- 9 kcal
- What it does
- Hormones, vitamins and recovery
- Where you find it
- Oils, butter, cheese, nuts, avocado, oily fish
| Macro | Calories per gram | What it does | Where you find it |
|---|---|---|---|
| Protein | 4 kcal | Builds and keeps muscle, and fills you up | Meat, fish, eggs, yoghurt, skyr, cottage cheese, beans, lentils, tofu |
| Carbohydrate | 4 kcal | Fuels training and everyday energy | Bread, rice, pasta, potatoes, oats, fruit, vegetables |
| Fat | 9 kcal | Hormones, vitamins and recovery | Oils, butter, cheese, nuts, avocado, oily fish |
That is why fat-heavy foods add up so fast: a gram of fat carries more than twice the calories of a gram of protein or carbs.
How to work out your macros in four steps
- Set your calories. Work out what you burn in a day from your size, age, job and training. To lose fat, eat about a fifth less; to build muscle, about 7.5% more; to stay the same, eat what you burn. If you have not done this yet, start with how many calories you should eat.
- Set your protein. About 2 g per kilo of body weight while losing fat, about 1.8 g per kilo to build muscle. More on this in how much protein you need a day.
- Set your fat. At least 0.8 g per kilo of body weight, or a quarter of your calories, whichever is more. Going lower for long is bad for hormones and recovery.
- Give the rest to carbs. Take the calories from protein (grams times 4) and fat (grams times 9) away from your total, and divide what is left by 4. That is your carbs in grams.
Worked example. A woman of 38, 5ft 4in and 10st 3lb (65 kg), with a desk job and three workouts a week, burns about 1,820 kcal a day. To lose fat she eats about 1,450. Protein is 2 g times 65, so 130 g, which is 520 kcal. Fat is the larger of 52 g (0.8 times 65) and 40 g (a quarter of 1,450, divided by 9), so 52 g, which is 468 kcal. That leaves 462 kcal for carbs: 116 g.
If your BMI is over 30, protein and fat are set from the weight you would be at a BMI of 30, so the targets stay realistic rather than asking for 250 g of protein a day.
Macros by aim: worked examples
Woman, 38, 5ft 4in, 10st 3lb (65 kg)
| Aim | kcal | Protein | Carbs | Fat |
|---|---|---|---|---|
| Lose fat | 1,450 | 130 | 116 | 52 |
| Build muscle | 1,950 | 117 | 249 | 54 |
Woman, 45, 5ft 5in, 12st 4lb (78 kg)
| Aim | kcal | Protein | Carbs | Fat |
|---|---|---|---|---|
| Lose fat | 1,570 | 156 | 97 | 62 |
| Build muscle | 2,110 | 140 | 248 | 62 |
Man, 35, 5ft 10in, 13st 5lb (85 kg)
| Aim | kcal | Protein | Carbs | Fat |
|---|---|---|---|---|
| Lose fat | 1,980 | 170 | 172 | 68 |
| Build muscle | 2,660 | 153 | 346 | 74 |
Man, 40, 6ft, 15st 10lb (100 kg)
| Aim | kcal | Protein | Carbs | Fat |
|---|---|---|---|---|
| Lose fat | 2,790 | 200 | 318 | 80 |
| Build muscle | 3,540 | 180 | 485 | 98 |
Protein, carbs and fat in grams a day. Worked out with the calculator on this page, November 2026. Desk job and three workouts a week, except the last person: on his feet all day, four workouts.
Notice that protein barely changes between losing fat and building muscle, and fat hardly moves at all. Calories and carbs are what change. That is the pattern for almost everyone.
Macros for weight loss
When you eat less, keep protein high, around 2 g per kilo. It protects your muscle so the weight you lose is mostly fat, and it fills you up more than carbs or fat, which makes the smaller amount of food easier to live with.
Fat stays at its minimum and carbs take the cut. You still need carbs to train well, so do not drop them to nothing; the calorie target does the work, not cutting a food group.
Macros to build muscle
You need a small surplus, about 7.5% over your burn, and around 1.8 g of protein per kilo. Most of the extra calories go to carbs, because carbs fuel the training, and the training is what builds the muscle.
Eating far more than that adds fat faster than muscle. A slow gain of about 0.2% of your body weight a week is the aim.
Macros for women
The rules per kilo are the same for women and men. Totals are usually lower because women tend to weigh less and burn less, which is also why a fixed macro split copied from someone else rarely fits. Many women eat well under half their protein target without realising, especially at breakfast.
Why not a fixed split like 40/30/30?
A percentage split ignores your body weight. On a small calorie budget, 30% protein can leave you short of what your muscle needs; on a large one, 30% fat gives you more than you need. Setting protein and fat per kilo first, then filling the rest with carbs, gives a split that fits you, and it changes sensibly when your calories change.
How to track your macros
- Hit calories and protein first. Carbs and fat can swap from day to day; the weekly average is what counts.
- Read the label: UK packs list energy, fat, carbohydrate and protein per 100 g and usually per portion.
- Build each meal around a protein, then add carbs and vegetables. Our high-protein supermarket meals guide has ideas.
- Members of Zama Fitness log in seconds: scan the barcode on the pack, or pick the dish from the menus of twenty UK chains, and it counts against the day's macros.
For meal ideas that fit, see high-protein supermarket meals.
Macros: your questions.
What are macros?
Macros, short for macronutrients, are the three nutrients that give food its calories: protein, carbohydrate and fat. Protein and carbohydrate have about 4 kcal per gram and fat about 9 kcal per gram.
How do I calculate my macros?
Work out your calories first, from your daily burn and your aim. Then set protein per kilo of body weight (1.8 to 2 g if you train), set fat at no less than 0.8 g per kilo or a quarter of your calories, and give carbs whatever calories are left. The calculator on this page does all four steps.
What should my macros be to lose weight?
Eat about a fifth fewer calories than you burn, keep protein high at about 2 g per kilo of body weight, keep fat at no less than 0.8 g per kilo, and let carbs fill the rest. A woman of 10st 3lb with a desk job who trains three times a week gets about 1,450 kcal: 130 g protein, 116 g carbs and 52 g fat.
What are good macros for building muscle?
Eat slightly more than you burn, about 7.5% over, with about 1.8 g of protein per kilo of body weight, fat at no less than 0.8 g per kilo, and the rest as carbs to fuel training. Carbs go up most, because training is what builds the muscle.
What macros should a woman eat to lose weight?
The same rules per kilo as a man: protein about 2 g per kilo, fat at least 0.8 g per kilo, carbs for the rest. The totals are usually lower because women tend to weigh less and burn less. Put your own numbers into the calculator.
Do I have to hit my macros exactly every day?
No. Calories and protein matter most. Getting within about 5% of your calories and close to your protein most days is enough; carbs and fat can swap with each other from day to day. What counts is the average over the week.
Is a 40/30/30 macro split good?
Fixed percentage splits ignore your body weight. A 40/30/30 split on a low calorie budget can leave you short of protein, and on a high one give you more fat than you need. Setting protein and fat per kilo, then filling the rest with carbs, fits the person, not the percentage.
What are my macros on Mounjaro or other weight-loss medication?
Protein is usually set lower than for someone training hard without medication: most UK guidance suggests 1.2 to 1.6 g per kilo, and our medication support plan starts at 1.4 g. Your prescriber or a dietitian can set the right figures for you.
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