What Is Protein and Why Are Protein-Rich Foods So Important?

Protein is one of the three main macronutrients, alongside carbohydrates and fats. It is found in every cell of the body and is essential for building and repairing tissue. This article explains what it is, what it does, how much you need to eat and where to find it.

What protein is

Proteins are chains of amino acids. The body uses around twenty different amino acids, and nine of them are considered essential because the body cannot make them and has to get them from food. When a food contains all nine in suitable amounts, its protein is called complete. Meat, fish, eggs and dairy are examples, as are soy and quinoa.

What it does

• Muscles and tissue: it helps build and maintain muscle mass, skin, hair and nails.
• Enzymes and hormones: many enzymes and some hormones are proteins.
• Defences: the antibodies of the immune system are made of protein.
• Fullness: meals with protein tend to be more filling, which helps control appetite through the day.
• Recovery: after exercise or injury, the body needs protein to repair tissue.

How much protein you need

For a healthy, fairly inactive adult, the usual reference is about 0.8 grams per kilogram of body weight per day. People who train regularly, especially with weights, may need more, and sports guidance typically points to between 1.2 and 2 grams per kilogram. Older adults also benefit from a slightly higher intake to preserve muscle. Instead of counting grams, a practical rule is to include a protein source in every main meal.

Best protein sources

Animal sources:

• fish, shellfish and lean poultry;
• eggs, one of the highest-quality proteins;
• plain yoghurt, fresh cheese, cottage cheese and milk.

Plant sources:

• pulses such as beans, chickpeas, lentils and peas;
• tofu, tempeh and other soy products;
• nuts, seeds and nut butters;
• wholegrains such as oats, and quinoa.

People following a vegetarian or vegan diet can meet their needs by varying sources through the day, for example combining grains with pulses.

How to spread it through the day

Rather than eating most of it at dinner, spread protein across your meals. Eggs or yoghurt with seeds at breakfast, fish or pulses at lunch, and fresh cheese or a handful of nuts as a snack are simple examples. This spread supports fullness and helps maintain muscle.

An example of a day with enough protein

To make this practical, one possible day for an active adult would be: at breakfast, two slices of wholemeal bread with scrambled egg and a piece of fruit; at lunch, a plate of chickpeas with vegetables and a grilled fish fillet; as a snack, plain yoghurt with walnuts; at dinner, roast chicken with boiled potatoes and a salad. Without counting a single gram, this spread already includes protein at every meal and, for most people, covers daily needs.

Protein supplements

Protein powders can be useful for people who struggle to meet their needs from food alone, such as some athletes or people with a small appetite. Most people do not need them. If you choose one, read the ingredient list, avoid products with lots of added sugar and do not rely on them to replace full meals regularly.

Things to watch

Eating too much protein brings no extra benefit and can put extra strain on people with kidney disease. Anyone with kidney problems, who is pregnant, who is frail and elderly or who has a chronic illness should talk to a doctor or dietitian before raising their intake significantly.

In short

Protein is essential for building and repairing the body and helps you feel full. Mixing animal and plant sources and including them at every meal is the simplest strategy. This article is for information only and does not replace advice from a health professional.