If you lift, the protein figure on most UK food labels and NHS pages is not the one you are after. That figure is set to keep an average adult healthy, not to help you build muscle.
The UK guideline is a floor, not a target
The UK reference nutrient intake for adults is 0.75 g of protein per kilogram of body weight a day. For an 80 kg person that is 60 g. It was set to cover the needs of almost everyone in the population, and it assumes nobody is trying to add muscle.
What the research says for people who train
The most cited answer comes from a 2018 meta-analysis of 49 studies by Morton and colleagues in the British Journal of Sports Medicine. Across people doing resistance training, extra protein kept adding to muscle gains up to about 1.6 g per kg a day, and some people kept benefiting up to about 2.2 g per kg.
The International Society of Sports Nutrition lands in the same place: 1.4 to 2.0 g per kg a day for most people who exercise.
What that means in grams a day:
| Body weight | 1.6 g per kg | 2.2 g per kg |
|---|---|---|
| 60 kg | 96 g | 132 g |
| 70 kg | 112 g | 154 g |
| 80 kg | 128 g | 176 g |
| 90 kg | 144 g | 198 g |
When to aim higher
Protein matters more when you are eating less. In a calorie deficit your body is more willing to use muscle for fuel, so most of the evidence on cutting points to the upper end of the range or above it. More on that in cutting without losing muscle.
That is why Liftprep sets 1.8 g per kg when you are building and 2.2 g per kg when you are losing fat.
Spread it through the day
You do not need to hit an exact number at every meal, but four meals with a decent amount of protein each beats one huge dinner. A 2018 review by Schoenfeld and Aragon suggests about 0.4 g per kg per meal across at least four meals. For an 80 kg person that is roughly 32 g a meal.
What that looks like in food
| Food | Protein per 100 g |
|---|---|
| Chicken breast, raw | 24.0 g |
| Tuna, tinned in brine | 24.9 g |
| Extra lean beef mince (5%) | 21.9 g |
| Quark | 14.6 g |
| Eggs | 12.6 g |
| Red lentils, dried | 25.6 g |
Figures from CoFID, the UK government's food composition data. There is a longer list in the best high-protein foods at a UK supermarket, and a worked example in high-protein meal prep for the week.
The short version
- Aim for 1.6 to 2.2 g per kg a day if you train.
- Go towards the top of that when you are cutting.
- Split it across four meals or so.
- Food first. Shakes are a convenience, not a requirement.
Liftprep works your target out from your weight and goal, then builds a week of meals that hits it. Try the free calculator.
Sources
- Department of Health (1991). Dietary Reference Values for Food Energy and Nutrients for the United Kingdom.
- Morton RW et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine 52: 376–384.
- Jäger R et al. (2017). International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition 14: 20.
- Schoenfeld BJ, Aragon AA (2018). How much protein can the body use in a single meal for muscle-building? Journal of the International Society of Sports Nutrition 15: 10.