The food you eat every day can affect how long you'll live, what diseases you develop, how you look and feel.
To be healthy, you need to eat a balanced diet - one that contains all the right nutrients, in the amounts the body needs.
The main essential nutrients in a balanced diet are.
Fats, as a slow-release energy supply.
Carbohydrates, needed for quick release energy.
And proteins for growth and repair.
Our bodies also need tiny quantities of vitamins and minerals.
Vitamins and Minerals
For example, vitamin D is essential for healthy bones.
And iron is a mineral important for carrying oxygen around your body in your red blood cells.
Fiber and Water
A healthy diet should also contain lots of fiber and water.
Fiber is the roughage in food that can't be digested, but is important to keep the intestines healthy and protect against bowel cancer.
To make sure you eat the right amounts of all these crucial nutrients and fiber, we can think of foods in terms of five main groups.
1. Starchy foods
Starchy foods should make up about a third of your diet. They include rice, pasta, root vegetables, pulses, and bread.
2. Fruit and vegetables
Another third should be fruit and vegetables - rich in vitamins and minerals.
3. Milk and dairy
Milk and other dairy foods are important sources of protein and calcium.
4. Protein-rich foods
And a similar amount of nondairy sources of protein are needed, such as meat, fish, beans and nuts.
5. Energy-dense foods
Finally, foods high in fat or sugar should only form a very small proportion of your diet.
The main food groups can be arranged as a pyramid to help clearly show the different amounts needed.
Although the exact foods eaten can vary around the world, these main building blocks of a healthy diet are universal.
The key is to stick to the correct proportions of different food groups and get as much variety as possible.