Protein: How Much, When and Why

The building block for muscle, recovery and staying full

Protein does far more than build muscle. It grows, repairs and maintains every tissue in your body, drives your metabolism, supports your immune system, and helps you feel full. Whether your goal is performance, fat loss or simply eating well, getting enough protein is one of the highest-value habits in nutrition.

What protein does

Growth, repair and maintenance of all body tissue.
Muscle development, contraction and movement.
Antibodies that support your immune system.
Builds enzymes and hormones, and provides backup energy when carbohydrate is low.

How much do you need?

You are	Daily protein target	Notes
A general UK adult	0.75 g per kg	The RDA (about 45 g women, 56 g men). Reduces deficiency risk, but likely low if you train.
Active or losing weight	1.2 to 2.0 g per kg	Protects muscle, especially in a calorie deficit.
Endurance training	around 1.2 to 1.9 g per kg	Spread across the day for best effect.
Strength training	around 1.4 to 2.0 g per kg	Benefits above roughly 2 g/kg are unclear; extra is simply burned for energy.

Timing matters as much as total

Your muscles rebuild through a process called muscle protein synthesis, switched on by training and by eating protein. To keep it topped up, spread protein across the day rather than loading it all at dinner. Around 20 to 40 g of quality protein per meal, across 3 to 4 meals, works well for most people, and a serving before bed can help too. Older adults need a little more per meal to trigger the same effect.

Quality and sources

Animal sources

Meat and poultry
Fish and eggs
Dairy and whey
Typically "complete" (all essential amino acids)

Plant sources

Beans, peas and lentils
Tofu and soya
Nuts and seeds
Combine a variety across the day to cover the essentials

Proteins are built from 20 amino acids, 9 of them essential and needed from food. Higher-quality proteins provide more of the essentials, but a varied mixed diet covers them.

Where to learn more: the NHS, the British Nutrition Foundation, the British Dietetic Association (BDA), and the Sport and Exercise Nutrition register (SENr). For advice tailored to you, please speak to your GP or a registered dietitian.

This leaflet is general nutritional guidance for education only. It is not medical advice, diagnosis or treatment, and it does not replace advice from your GP or a registered dietitian. Always check with a qualified professional before making significant changes, particularly if you have a health condition, are pregnant, or take medication.