How much protein do you actually need? The UK numbers

Ask the internet how much protein you need and you will get answers ranging from 45 grams a day to 200. The reason is not that anyone is lying. It is that two entirely different numbers are being quoted, for two entirely different purposes, usually without saying which.

Here are both, with sources.

The official UK figure

The UK reference nutrient intake for protein is 0.75 grams per kilogram of body weight per day for adults.

Translated into the figures usually quoted, that is roughly 56 grams a day for men and 45 grams a day for women, based on reference body weights of 75kg and 60kg.

It is worth understanding what an RNI actually is. It is the amount judged sufficient for around 97% of the population, a level set to prevent deficiency across a whole country. It is a floor, not a target, and it was never designed with resistance training in mind.

The sports nutrition figure

For people doing vigorous physical activity or following a strength-based training programme, the American College of Sports Medicine puts the range at 1.2 to 2.0 grams per kilogram per day.

For an 80kg person that is 96 to 160 grams a day, against an RNI of 60 grams. Both numbers are defensible. They are answering different questions: one is “what stops deficiency”, the other is “what supports adaptation to training”.

Most of the arguing online is people quoting one number at someone using the other.

Working out your own

Take your body weight in kilograms and pick the multiplier that matches your actual situation, not your aspirational one.

• Not training, generally sedentary: 0.75g/kg is the reference intake.
• Training regularly, including two strengthening sessions a week: the 1.2 to 2.0g/kg range is where the sports nutrition guidance sits. Most people in this group land nearer the bottom of it than the top.
• Over 50 and training: the RNI table shifts only slightly with age, but the practical case for sitting at the higher end is stronger, because the muscle-building response to a given amount of protein becomes less pronounced with age.

Distribution matters more than people expect

A common pattern in the UK is a light breakfast, a modest lunch, and most of the day’s protein arriving at dinner. The daily total can look fine on a tracking app while the distribution is heavily skewed.

Spreading intake across meals is generally considered more useful than hitting the same total in one sitting. Practically, that usually means fixing breakfast, which for most people is the thinnest meal of the day.

Where it should come from

Food first, and this is not a moral position: it is that whole foods bring other things with them.

• Animal sources: meat, fish, eggs, dairy
• Plant sources: beans, lentils, chickpeas, tofu, tempeh, nuts, seeds
• Convenience: Greek yoghurt, tinned fish, cottage cheese, frozen edamame

Protein powder is a convenience product, not a category of nutrition. It is useful when you are short and short on time. It is not doing anything a chicken breast is not.

The honest caveat

Very high protein intakes are not automatically better, and if you have reduced kidney function this is a conversation for your GP rather than a website or a supplement brand. For most healthy adults, the range above is well-trodden ground.

Sources

British Nutrition Foundation, Protein. Reference nutrient intake of 0.75g per kg body weight per day for adults.

American College of Sports Medicine, 1.2 to 2.0g per kg per day for those undertaking vigorous activity or strength-based training.

General information, not medical advice. If you have a health condition, particularly affecting the kidneys, speak to your GP before making large changes to protein intake.