Nutrition science
How much protein do you need? A dietitian's guide
· Reviewed by James, Dietitian
Most healthy adults need 0.8–1.0 g of protein per kg of body weight a day. That's about 55–70 g for a 70 kg person. If you're losing weight, lifting weights or over 65, aiming higher, roughly 1.0–1.6 g/kg, is well supported. Going much past 1.6 g/kg adds little for most people.
The rest of this guide explains where those numbers come from and how to pick yours. If you'd rather skip the maths, the macro calculator works it out from your weight, height, age, activity and goal.
The baseline: what "enough" means
Official reference values set the minimum that covers the needs of nearly all healthy adults (97.5% of them):
- UK: 0.75 g per kg of body weight a day, the Reference Nutrient Intake set in 1991 (Department of Health, Dietary Reference Values).
- EU: 0.83 g/kg a day, for protein from a normal mixed diet (EFSA, 2012).
These describe what prevents a shortfall. For everyday eating, around 0.8–1.0 g/kg a day is a sensible target for healthy adults. For a 60 kg adult that's 48–60 g a day, and for an 80 kg adult 64–80 g. Most people in Europe already eat around this much.
Expert groups have set higher figures for the situations below.
Losing weight
When you eat less than you burn, some of the weight you lose comes from muscle, not just fat. Eating more protein reduces that. Controlled studies show that higher-protein diets during weight loss keep more lean mass and help a little with fullness. The benefit depends heavily on actually sticking to it (Leidy et al., 2015). Why protein keeps you fuller.
A sensible range while losing weight is roughly 1.2–1.6 g/kg: towards the lower end if you're mostly sitting down, and the upper end if you're also training.
Building muscle
Protein only builds muscle alongside resistance training. Without the training, extra protein just gets used as energy.
The best summary of the evidence is a 2018 meta-analysis of 49 trials. Extra protein increased the muscle gained from resistance training, but the benefit levelled off at about 1.6 g/kg a day (Morton et al., 2018). The study's confidence range ran up to 2.2 g/kg, so some people may benefit from a little more. The International Society of Sports Nutrition recommends 1.4–2.0 g/kg for people who exercise regularly (Jäger et al., 2017).
Much higher intakes, such as 3 g/kg, have mainly been studied in lean athletes dieting hard. For everyone else, they mostly crowd out foods that bring fibre, vitamins and minerals.
Over 65
Older muscle responds less to protein. A 70-year-old needs more protein in a meal than a 20-year-old to get the same muscle-building response (Moore et al., 2015).
For healthy people over 65, the international PROT-AGE expert group recommends at least 1.0–1.2 g/kg a day. That's 70–84 g for a 70 kg person. It recommends 1.2 g/kg or more for those who are active, and 1.2–1.5 g/kg for people with an acute or long-term illness (Bauer et al., 2013). The important exception is severe kidney disease, where protein may need to be limited. That's a decision for your doctor or renal dietitian.
Two practical points matter more at this age than the exact daily figure:
- Spread it out. Aim for a decent serving of protein at each meal rather than most of it at dinner. In the study above, about 0.4 g/kg per meal maximised the response in older men. That's around 28 g for a 70 kg person.
- Keep moving. Strength exercise and protein work together. Neither does much for muscle on its own.
Vegetarian and vegan diets
You can get enough protein without meat. Well-planned vegetarian and vegan diets are nutritionally adequate at every stage of life (Academy of Nutrition and Dietetics, 2016).
Plant proteins differ from animal ones in two ways. They are a little less digestible, and individual foods tend to be low in one or more essential amino acids. Grains, for example, are low in lysine, which beans and lentils supply. You don't need to combine foods in the same meal. Eating a variety across the day covers it.
In practice:
- Build meals around a protein-rich plant food. Tofu, tempeh, lentils, beans, chickpeas, edamame or a mycoprotein such as Quorn.
- If you eat eggs and dairy, use them. They're complete proteins and add useful iodine and B12.
- Most of your protein comes from plants? Aiming slightly above the bottom of your range gives a sensible buffer.
How much protein is in common foods
Values are from CoFID, the UK government's food composition tables.
| Food | Portion | Protein |
|---|---|---|
| Chicken breast, grilled | 120 g | 38 g |
| Tuna, canned in brine, drained | 100 g | 25 g |
| Tempeh | 100 g | 21 g |
| Edamame, boiled | 150 g | 18 g |
| Red lentils, boiled | 200 g | 16 g |
| Eggs (2 large) | 120 g | 15 g |
| Quorn pieces | 100 g | 14 g |
| Baked beans | 200 g | 10 g |
| Semi-skimmed milk | 250 ml | 9 g |
| Cheddar | 30 g | 8 g |
| Peanut butter (2 tbsp) | 30 g | 7 g |
Weights for meat and pulses here are cooked. 120 g of grilled chicken starts as roughly 170 g raw. Why raw and cooked weights matter.
Is a high-protein diet safe?
For healthy adults, yes, within the ranges above. A 2018 meta-analysis of 28 studies found that higher-protein diets (at least 1.5 g/kg a day) didn't harm kidney function in people with healthy kidneys (Devries et al., 2018).
Speak to your GP or a dietitian before raising your protein if any of these apply:
- you have kidney disease, or have been told your kidney function is reduced;
- you're pregnant or breastfeeding, when needs rise;
- you have, or have had, an eating disorder;
- you're under 16.
Working out your number
Pick the line that fits you, then multiply by your weight in kg:
| Your situation | Grams per kg a day |
|---|---|
| Healthy adult | 0.8–1.0 |
| Over 65 | 1.0–1.2 |
| Losing weight | 1.2–1.6 |
| Regular strength training | 1.4–2.0 |
If your BMI is over 30, use an adjusted weight instead of your full weight. Fat tissue doesn't need protein in the way muscle does, so multiplying by total weight overshoots. At 1.6 g/kg, a 120 kg man would be told to eat about 190 g of protein a day. That's around 600 g of cooked chicken.
How BiteSync sets your protein
BiteSync is our app.
BiteSync works out your protein target from two things you tell it: how active you are and your goal. These are the figures it uses, in grams per kg of body weight a day:
| Activity | Maintain | Lose weight or build muscle |
|---|---|---|
| Sedentary | 1.0 | 1.2 |
| Lightly active | 1.1 | 1.2 |
| Moderately active | 1.4 | 1.6 |
| Very active | 1.6 | 1.8 |
| Extremely active | 1.8 | 2.0 |
Above a BMI of 30, it bases protein on an adjusted weight: your ideal weight plus a quarter of the difference. Some examples, worked out with BiteSync's own code:
- 70 kg woman, desk job, maintaining: 70 g a day.
- 70 kg woman, exercising 3–5 times a week, losing weight: 112 g a day.
- 80 kg man, training hard most days, building muscle: 144 g a day.
- 120 kg man, 175 cm, lightly active, losing weight: 99 g a day. Without the adjustment it would be 144 g.
When BiteSync Pro fills your week, it aims for every day to reach at least 95% of that target, and tells you which days fall short.
Work out your protein and calories. It's free, needs no sign-up, and nothing you enter is sent anywhere.
Quick answers
How much protein do I need a day to lose weight? About 1.2–1.6 g per kg of body weight. That's 84–112 g for a 70 kg person. Use the upper end if you're also strength training.
How much protein do I need to build muscle? About 1.6 g/kg a day, alongside regular resistance training. Some people go up to 2.2 g/kg, but for most it adds little.
Is 100 g of protein a day too much? Not for most healthy adults. For someone weighing 70 kg it's about 1.4 g/kg, well within the ranges above. If you have kidney disease, check with your doctor.
Do I need protein shakes? No. They're a convenient way to add protein, not a requirement. Food covers most people's needs, as the table above shows.
Should I eat protein at every meal? It helps, especially if you're over 65 or trying to build muscle. Spreading protein over three or four meals uses it better than eating most of it at dinner.