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Overall good health depends on a good diet, and nutritional requirements vary at different stages of life. For healthy and well balanced nutrition, frequent recommendations are the Mediterranean diet and the low-GI diet. Mediterranean diet: rich in plant-based foods - fruits and vegetables, pulses (peas and beans), wholegrain cereals - and fish, with some olive oil but low in meat and dairy products, and with just a small amount of foods high in fat, salt and sugar. Low GI diet The glycaemic index (GI) ranks carbohydrates from 0 to 100 according to how much they raise blood sugar levels after eating. High-GI foods are rapidly digested and absorbed, causing marked fluctuations in blood sugar. Low-GI foods, slowly digested and absorbed, produce gradual rises in blood sugar and insulin levels, and have proven benefits for health. A low-GI diet improves glucose and lipid levels in people with diabetes (type 1 and type 2), reduces insulin levels and insulin resistance, and has benefits for weight control (helps control appetite and delay hunger).

Diabetes UK Glycaemic index and diabetes.

GI food search tool (University of Sydney)

General guide

A suitable guide for most individuals is the Eatwell Plate, which shows the recommended balance between the five major food groups:

  • bread, rice, potatoes, pasta and other starchy foods (carbohydrates)
  • fruit and vegetables
  • milk and dairy foods
  • meat, fish, eggs, beans and other non-dairy sources of protein
  • foods and drinks high in fat and/or sugar.

Modified diets

Patients who are overweight or underweight, who have certain conditions, e.g. diabetes, hyperlipidaemia, or who wish to avoid eating animal products may need advice on a suitable diet.


The body needs a range of nutrients to remain healthy and function efficiently. Carbohydrate, protein and fat are ‘macronutrients’, needed in relatively large amounts as they provide both energy and building blocks for growth and body maintenance. Vitamins, minerals and trace elements are ‘micronutrients’, needed in small amounts but essential to health. The major nutrients required and present in food are proteins, carbohydrates and fats. Dietary fbre, while strictly a nutrient as it is not digested and absorbed into the body, is also essential for good health.

Proteins: found mainly in meat, fish, eggs, milk, pulses, nuts and seeds. They are needed for the growth, maintenance and repair of cells. Food proteins are digested to their constituent amino acids, which are used to build the proteins needed by the cells of the body.

Carbohydrates: present in starchy or sugary foods. Carbohydrates provide the body’s main source of immediate energy.

Fats: derived from animal or plant sources, eg butter, olive oil. Fats are a more concentrated source of energy and are important in building the membranes found around and within cells.

Fibre: sources include bran cereals, wholemeal flour, rice and pasta, beans, green vegetables and fruit.


Our bodies also need a range of vitamins, minerals and trace elements.

Vitamins are essential nutrients needed in small amounts for growth and development; the body cannot survive without them. There are two types.

  • fat-soluble vitamins (A, D, E, K): found in animal fats (including butter and lard), vegetable oils, dairy products, liver and oily fish. Transported around the body in fat, and stored in the liver and fatty tissues (except for vitamin D in winter).
  • water-soluble vitamins (vitamin B6, B12, C, biotin, folic acid , niacin, pantothenic acid, riboflavin, thiamin): found in meat, fruit, vegetables and wholegrains. Transported around the body in water; can't be stored as excess is lost in urine. Can be destroyed by heat or exposure to air, and lost in cooking water; best retained by steaming or grilling rather than boiling.

Minerals are essential nutrients needed in small amounts for strong bones and teeth, for control of body fluids, and for turning food into energy. We need them in the form they are found in foods such as meat, cereals (including cereal products such as bread), fish, milk and dairy foods, vegetables, fruit (especially dried fruit) and nuts. Essential minerals are calcium, iron, magnesium, phosphorus, potassium, sodium, sulphur.

Trace elements are essential nutrients needed in very small amounts, found in a variety of food. They are boron, cobalt, copper, chromium, fluoride, iodine, manganese, molybdenum, selenium, silicon, zinc.

Energy requirements

The body needs energy to carry out vital activities and maintain itself at a constant temperature. The energy in food is measured in Joules or kilocalories. Each individual’s calorific requirement depends upon their height, weight, sex, age, normal daily activity levels and inherent basal metabolic rate. An average man needs up to c. 2550 kcal per day, while even an active woman needs only c. 1940 kcal. A woman's requirements can be higher during pregnancy or if she is breastfeeding. Energy not used is stored, usually as fat. Even a little surplus energy intake each day can lead to weight gain.

Food fact sheets British Dietetic Association

Practice Nurse featured article

Obesity for general practice nurses Dr Gerry Morrow 


Results when a person eats too little food or the wrong balance of basic food groups (an obese person can be malnourished); associated with poor wound healing, impaired immune responses, and delayed recovery from illness. Most at risk are people who are:

  • elderly
  • on low incomes or socially isolated
  • have chronic disease e.g. COPD
  • are recovering from serious illness, e.g. stroke

Malnutrition Universal Screening Tool (MUST) includes a 5-step screening tool to identify adults, who are malnourished, at risk of malnutrition (under-nutrition), or obese: management guidelines

BAPEN. Practical guidance for using MUST to identify malnutrition during the COVID-19 pandemic. Malnutrion Action Group (MAG) update; 2020

NICE CG32 Nutrition support in adults: oral nutrition support, enteral tube feeding and parenteral nutrition, 2006

British Association for Parenteral and Enteral Nutrition (BAPEN).

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