How much protein should I eat a day?
To stay healthy, adults need at least 0.75 g of protein per kilo of body weight a day. To lose fat without losing muscle, or to build muscle, you need more: about 1.8 to 2 g per kilo. On Mounjaro, most guidance suggests 1.2 to 1.6 g. Work out your own number below.
By Simon, head coach at Zama Fitness. Updated 24 October 2026.
Protein calculator
Eat about
160 gof protein a day
That is about 53 g at each of your 3 meals, or 2.0 g per kg of body weight.
Higher protein while you eat less keeps your muscle, so the weight you lose is mostly fat. It also keeps you fuller.
A target is the easy part; hitting it every day is harder. Members get meals and a UK shopping list built to hit it.
For adults aged 18 and over. If you have kidney disease or another health condition, speak to your GP before changing your diet.
How much protein a day: by aim
How much protein you need depends on what you want your body to do with it. Worked out with the calculator above:
| Height and weight | Stay healthy | Lose fat | Build muscle | On weight-loss medication |
|---|---|---|---|---|
| 5ft 4in, 10st 3lb (65 kg) | 49 g | 130 g | 117 g | 91 g |
| 5ft 5in, 12st 4lb (78 kg) | 59 g | 156 g | 140 g | 109 g |
| 5ft 10in, 13st 5lb (85 kg) | 64 g | 170 g | 153 g | 119 g |
| 6ft, 15st 10lb (100 kg) | 75 g | 200 g | 180 g | 140 g |
Worked out with the calculator on this page, October 2026.
The healthy figure is the UK reference intake: enough to keep your body working, but not enough to protect your muscle while you eat less, or to build more of it.
Protein per day for women
Women need the same amount of protein per kilo as men; the total is usually lower simply because women tend to weigh less. A woman of 10st 3lb aiming to lose fat needs about 130 g a day, and about 117 g to build muscle.
Many women eat well under half of that without realising, especially at breakfast and lunch. That is one of the most common reasons for feeling hungry on a diet and for losing muscle along with the fat.
Protein per day to lose weight
When you eat fewer calories, protein becomes more important, not less. Around 2 g per kilo a day helps you keep your muscle, so the weight you lose is mostly fat. Protein also fills you up more than carbs or fat, which makes eating less easier.
If you are working out how much to eat overall, start with how many calories you should eat to lose weight, then fit your protein into it.
How much protein to build muscle
About 1.8 g per kilo a day is enough to build muscle for most people, as long as you train with weights at least twice a week. The training is what builds the muscle; the protein is what lets you keep and grow it.
Spreading it across the day, at 25 to 40 g a meal, works better than one big protein meal at night.
How much protein on Mounjaro?
Most UK pharmacies and dietitians writing about Mounjaro and other weight-loss medicines suggest 1.2 to 1.6 g of protein per kilo a day. To use the calculator above as a Mounjaro protein calculator, choose "On weight-loss medication": it shows a figure in that range, and our medication support plan starts at 1.4 g.
The hard part is appetite. Your Mounjaro protein intake tends to fall without you noticing, because smaller meals mean less of everything. When you are not hungry, eat the protein part of each meal first, and choose foods that go down easily. Your prescriber or a dietitian can set the right figure for you.
When to eat your protein
Spread it across the day. Three or four meals of 25 to 40 g each work better for keeping and building muscle than one large protein meal in the evening, and they keep you fuller between meals.
Breakfast is where most people fall short. Toast or cereal on its own has very little protein, so adding eggs, yoghurt or skyr makes the biggest single difference to your daily total.
Protein in everyday UK foods
| Food | Protein |
|---|---|
| Chicken breast, cooked | about 30 g per 100 g |
| Tinned tuna, drained | about 25 g per 100 g |
| Skyr or fat-free Greek-style yoghurt | about 10 g per 100 g |
| Cottage cheese | about 11 g per 100 g |
| Eggs | about 6 to 7 g each |
| Lentils, cooked | about 9 g per 100 g |
Approximate values. Check the label on the product you buy.
- Build each meal around one of these, then add vegetables and carbs.
- Keep a quick option in the fridge for days you are short: yoghurt, cottage cheese or cooked chicken.
- A protein shake is a convenient top-up, not a replacement for meals.
Protein: your questions.
How much protein should I eat a day?
The UK reference intake for adults is 0.75 g per kilo of body weight. If you train or want to lose fat without losing muscle, you need more: we set 1.8 to 2 g per kilo for members. Use the calculator for your own number.
How much protein per day for women?
The same per kilo as men. A woman of 10st 3lb (65 kg) needs about 49 g a day to stay healthy, about 117 g to build muscle and about 130 g while losing fat.
How much protein do I need to lose weight?
About 2 g per kilo of body weight a day while you are eating less. Higher protein protects your muscle, so the weight you lose is mostly fat, and it keeps you fuller on fewer calories.
How much protein do I need to build muscle?
About 1.8 g per kilo of body weight a day, as long as you train with weights two or more times a week. Eating more than that adds little extra muscle.
How much protein should I eat on Mounjaro?
Most UK pharmacies and dietitians writing about these medicines suggest 1.2 to 1.6 g per kilo a day. Our medication support plan starts at 1.4 g. Your prescriber or a dietitian can set the right figure for you.
What is the best protein shake while on Mounjaro in the UK?
Look for a shake with 20 to 30 g of protein, little added sugar and a small serving you can finish when your appetite is low. Ready-to-drink shakes from UK supermarkets are fine. Check with your prescriber if a shake upsets your stomach.
Can you eat too much protein?
For healthy adults, the amounts on this page are well within what is considered safe. If you have kidney disease or another health condition, speak to your GP before increasing your protein.
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