Nutrients, what each of them does and how much you need a day

What each nutrient does

• Protein contributes to the maintenance of muscle mass and to the maintenance of normal bones.
• Carbohydrate provides energy. Carbohydrates contribute to the maintenance of normal brain function. Starchy foods such as potatoes, bread, rice, pasta and oats provide most of it.
• Fat provides energy and essential fatty acids, and helps the body absorb vitamins A, D, E and K.
• Fibre comes from wholegrains, pulses, fruit and vegetables, and most adults in the UK do not eat enough of it.
• Water carries everything else around the body.

Daily nutrient benchmarks

As a guide, the NHS guide to calories gives 2,000kcal a day for an average woman and 2,500kcal for an average man. Needs vary with age, height, weight and activity.

• Starchy foods should make up just over a third of what you eat, and so should fruit and vegetables, according to the NHS Eatwell Guide.
• Fibre. Government guidelines say adults should aim for 30g a day. Most adults eat only about 20g, as the NHS fibre guide points out.
• Saturated fat. No more than 30g a day for men and 20g for women, in the NHS guide to fats.
• Salt. No more than 6g a day, around 1 level teaspoon.
• Fluids. 6 to 8 cups or glasses a day, more in hot weather or when you are active.

The full Eatwell Guide on GOV.UK sets out these proportions for the whole day rather than for every single meal.

Pregnancy and breastfeeding are different

During pregnancy and breastfeeding, some needs change, including folic acid and vitamin D. Your midwife or GP is the right person to guide you. Pregnancy is not the time for a weight loss diet.

Nutrients while you change your eating

When you eat a little less, quality matters more. Keep a source of protein at every meal, choose wholegrain starchy foods and fill half your plate with vegetables. Cutting a whole food group, such as all carbohydrate, makes the diet harder to keep and often less balanced.

Our articles on vitamins, minerals and how much protein you need per day go into each group in more detail. This article does not replace advice from your GP or another health professional.

At the Witney club

At our club, the day starts with a balanced breakfast taken together in the morning before work. The free assessment looks at how your usual meals compare with these benchmarks.