When it comes to staying healthy, protein is a key ingredient because it enables the body to grow and repair itself.
Protein is contained in all cells and tissues and is the second-most abundant compound in the body, after water.
Most of your protein is found in your muscles, your skin and blood, while your hair and nails are made of protein.
It gives the body about 10 to 15 per cent of its dietary energy. It is a source of vitamins and minerals. And protein-rich foods help you to feel fuller so you're less likely to snack or over-eat.
Your body's building blocks
Protein is made up of amino acids, the basic building blocks of the human body, and some of these are essential in an adult's diet.
Getting protein from animal sources, such as meat, fish, eggs, milk and cheese, will give you the full range of those acids. Choose low-fat versions if possible.
Source of vitamins
Meat is also a good source of vitamins and minerals, including iron, zinc and B vitamins.
Indeed, it is one of the main sources of vitamin B12, which makes red blood cells and keeps your nervous system healthy.
What to eat
Lean cuts of meat and skinless poultry can cut down the fat you eat, while you should try to manage how much red and processed meat you eat, such as bacon, ham and sausages.
Eggs and fish contain plenty of vitamins and minerals, with oily fish being particularly rich in omega-3.
Vegan sources of protein
Vegans and vegetarians can get all the amino acids they need by combining different plant sources of protein, like cereals.
Pulses, including beans, peas and lentils, are very low in fat but high in protein, fibre, vitamins and minerals.
How much to have
Adults and children should try to eat two to three servings of food high in protein every day.
In particular, having at least two portions of fish a week is recommended.