Biochemistry · Topic
Balanced diet !
A balanced diet gives enough energy for a healthy weight and every nutrient the body needs, from varied foods, with little sugar, salt and unhealthy fat.
Updated 2026-11-01
Key facts
- Energy intake should match expenditure, so that body weight stays in a healthy range.
- WHO adult targets: at least 400 g of fruit and vegetables a day, at least 25 g of fibre, free sugars under 10 % of energy (ideally under 5 %), salt under 5 g a day (iodised).
- Fats: total about 15–30 % of energy, saturated under 10 %, industrial trans fat avoided; prefer unsaturated plant oils, nuts and fish.
- Protein about 10–15 % of energy, from varied sources (legumes, cereals, eggs, dairy, fish, meat).
- Malnutrition has two faces: undernutrition (wasting, stunting, micronutrient deficiencies) and overweight/obesity, which can coexist in the same country and even the same household.
In detail
- 1. Variety: whole grains and tubers, legumes, vegetables and fruits, plus some animal foods (dairy, eggs, fish, meat) or well-planned plant alternatives.
- 2. Key micronutrients to watch: iron (anaemia), iodine (goitre, child brain development), vitamin A, zinc, calcium and vitamin D, folate before and during pregnancy.
- 3. Life stages: infants need exclusive breastfeeding for the first 6 months; pregnancy adds energy, protein, iron, folate and iodine needs; older adults need protein, calcium and vitamin D.
- 4. Ultra-processed foods and sugary drinks are the main source of free sugars, salt and trans fats in many diets.
- 5. National food-based guidelines translate these targets into food groups and portions (for example, the 'healthy plate' models).
- 6. Physical activity is part of the balance: it raises expenditure and improves insulin sensitivity.
- Also called
- Healthy diet, Dietary recommendations
Clinical notes
- Unbalanced diets drive the main non-communicable diseases: obesity, type 2 diabetes, hypertension, cardiovascular disease and some cancers.
- In children, poor diets cause stunting and wasting; in Latin America, undernutrition and childhood obesity now coexist.
- Salt restriction lowers blood pressure; replacing saturated with unsaturated fat lowers LDL cholesterol.
Related conditions
- Obesity
- Type 2 diabetes mellitus
- Arterial hypertension
- Iron deficiency anaemia
- Metabolic syndrome
- Atherosclerosis and dyslipidaemia
Related
- Macronutrients and the energy value of food
- Dietary fibre
- Protein quality and essential amino acids
- Energy requirements and basal metabolic rate (BMR)
- Iron
- Calcium and phosphate
- Iodine
Test yourself
Think of the answer, then tap the question to see it.
What daily amount of fruit and vegetables does WHO recommend for people over 10 years of age?
At least 400 grams a day.
What is the WHO limit for salt in adults?
Less than 5 g of salt a day, and it should be iodised.
What does the 'double burden of malnutrition' mean?
Undernutrition (wasting, stunting, micronutrient deficiency) and overweight or obesity occurring together in a population or household.
Which fats should be replaced, and by what?
Saturated and industrial trans fats, by unsaturated fats from plant oils, nuts and fish.
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Healthy diet (World Health Organization, 2026); Fact sheets - Malnutrition (World Health Organization, 2026); Nutrition: MedlinePlus (MedlinePlus, US National Library of Medicine, 2026); Healthy living: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).
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Representative model, for educational purposes only.