A healthy human diet

In a nutshell

A healthy human diet is made up of six nutrients and one essential component that keeps humans healthy. The human diet requires balance to maintain health and prevent disease.

Nutrients in a balanced diet

Carbohydrates, lipids (fats and oils), proteins, water, vitamins and minerals are all nutrients, this means they are essential to life. Fibre is also important in keeping the body healthy.

Carbohydrates

Carbohydrates are a nutrient essential for energy. There are two types of carbohydrates discussed in the table below.

Carbohydrate Type	Sources	image
Starchy	Bread, rice and pasta.
Sugary	Sweets, chocolates and cake.

Lipids

Lipids are also called fats. Fats are important because they provide the body with energy, they are also the building blocks of some hormones. There are two types of lipids discussed in the table below.

Lipid Type	Sources	image
Fats (saturated fat)	Meat, butter and cheese.
Oils (unsaturated fat)	Nuts, seeds and fish.

Proteins

Proteins are an essential element of the human diet because they are used to make new cells and fix damaged ones. Some sources of protein include meat, fish, eggs, milk and legumes.

Science; Human nutrition, digestion and health; KS3 Year 7; A healthy human diet

Vitamins

Vitamins are vital for general health. They are referred to as micronutrients because they are needed in small amounts. Vitamins are found in most foods but fruits and vegetables are especially rich in vitamins.

Vitamin	Sources	Function
A	Carrots	Healthy eyes
C	Oranges	Good immune function
E	Spinach	Healthy skin

Minerals

Minerals are also micronutrients essential for health. Different minerals have different functions.

Mineral	Sources	Function	Image
Iron	Red meat, fish and green leafy vegetables like broccoli.	Carries oxygen in red blood cells.
Calcium	Dairy products and green leafy vegetables.	Keeps bones and teeth strong.

Water

Water comes from fluids and fluid-rich foods like fruits, vegetables and soups. The body is around $60\%$ water and water therefore needs replenishing due to losses via urine, sweat and tears.

Science; Human nutrition, digestion and health; KS3 Year 7; A healthy human diet

Fibre

Fibre is found in a variety of foods but is indigestible and not absorbed, so technically it is not a nutrient. There are two types of fibre:

fibre TYPE	FUNCTION
Soluble	This kind of fibre dissolves in water and helps to draw water into food as it passes through the digestive system. This makes the final waste product (faeces) soft enough to pass.
Insoluble	This kind of fibre adds bulk to food and helps feelings of fullness.