Healthy diet: what the WHO and CDC recommend for adults and families

What we eat every day shapes our health over many years. This review explains what a healthy diet is, the main limits and targets from the World Health Organization (WHO), and practical tips from the US Centers for Disease Control and Prevention (CDC).

1. Introduction

WHO describes four principles of a healthy diet: adequacy (enough of each nutrient without excess), balance (energy intake matched to energy used, with a balance of protein, fat and carbohydrate), moderation (limiting harmful foods and ingredients) and diversity (a wide range of nutritious foods). The food must also be safe, free of germs and chemical contamination ^[1]. WHO stresses that the exact make-up varies with age, sex, lifestyle, activity level, culture and what food is available locally ^[1].

Healthy diets help protect against malnutrition and against noncommunicable diseases (long-term illnesses that do not spread from person to person) such as diabetes, heart disease, stroke and cancer ^[1]. The CDC also links healthy eating patterns to longer life ^[2].

2. Plant foods, fibre and carbohydrate

WHO advises that carbohydrates should make up roughly 45% to 75% of daily energy, mainly from whole grains, vegetables, fruit and pulses such as lentils, chickpeas and beans ^[1]. Adults and children over 10 should eat at least 400 g of fruit and vegetables every day, with smaller amounts for younger children ^[1]. Frozen and canned produce is fine if it has no added sugar or extra salt, while fruit juice, even without added sugar, contains free sugars and should be limited ^[1]. Dietary fibre from food, at least 25 g a day for people over 10, comes from the same plant foods ^[1].

3. Sugars, fats and protein

Sugars

Free sugars include added sugars and the sugars in honey, syrups, fruit juice and juice concentrates. WHO advises keeping them under 10% of daily energy, which is about 50 g (roughly 12 level teaspoons) on a 2,000 calorie diet, and says staying at or below 5% may give extra benefit ^[1]. WHO does not recommend swapping sugar for non-sugar sweeteners as a way to manage intake ^[1].

Fats

Adults need some fat, but total fat should stay at or below 30% of energy to help prevent unhealthy weight gain ^[1]. Saturated fat, found in fatty meat, butter, ghee, cream, cheese, palm and coconut oil, should be under 10% of energy, and trans fat, found in many baked, fried and packaged foods, under 1% ^[1]. Unsaturated fats from fish, nuts, avocado and oils such as sunflower, soybean, canola and olive are preferred ^[1]. Steaming or boiling instead of frying helps cut fat ^[1].

Protein

For most adults protein at 10% to 15% of daily energy is enough. It can come from plants and animals, and WHO notes that plant-based sources may lower diet-related disease risk in adults, while animal-source foods remain important for children and for pregnant or breastfeeding women ^[1].

4. Salt and potassium

WHO advises less than 5 g of salt a day, which equals less than 2 g of sodium ^[1]. Most salt comes from processed foods, frequently eaten foods such as bread, and salt or sauces added in cooking and at the table ^[1]. High sodium raises blood pressure and so raises the risk of heart disease ^[1]. Fresh fruit and vegetables supply potassium, which can offset part of sodium's effect on blood pressure ^[1]. WHO says lower-sodium salt substitutes suit only people who are not at risk of high potassium in the blood, so ask your doctor first, especially if you have kidney disease ^[1].

5. Vitamins and minerals

The body needs about 30 essential micronutrients, which are vitamins and minerals needed in small amounts ^[1]. WHO reports that deficiencies are common, with more than half of children under five and over two-thirds of non-pregnant women of reproductive age lacking at least one key micronutrient, typically iron, zinc, vitamin A or folate ^[1]. Beans and lean meat supply iron, dark leafy greens supply vitamin A, and iodised salt supplies iodine ^[1].

6. Putting it into practice

The CDC describes a healthy eating plan built on vegetables, fruit, protein foods, dairy without added sugars, healthy fats and whole grains, while limiting added sugars, salt, saturated fat, trans fat and cholesterol, and staying within your calorie needs ^[2]. Tips from the sources ^{[1, 2]}:

• Build meals around vegetables, fruit, whole grains and pulses.
• Try a new vegetable each week for variety.
• Bake, grill, steam or boil instead of frying, and try beans in place of some meat.
• Choose milk or yoghurt without added sugars.
• Choose canned fruit packed in water or its own juice, and canned vegetables without added salt.
• Use less salt and salty sauces in cooking, do not add salt at the table, and limit salty snacks.

WHO also advises exclusive breastfeeding for the first 6 months and continued breastfeeding to age 2 and beyond, with safe, varied foods from 6 months and no added salt or sugar ^[1].

7. Diet, weight and long-term disease

WHO states that a higher than optimal body mass index (BMI, a weight-for-height measure) caused an estimated 3.7 million deaths in 2023, mainly from heart disease, diabetes and cancers ^[3]. Eating a diet rich in fruit, vegetables, pulses, whole grains and nuts while limiting fat, sugar and salt is part of its advice for preventing overweight ^[3].

8. When to see a doctor

See a doctor or a registered dietitian if you have diabetes, kidney disease, heart disease or high blood pressure and are changing your diet, if you are pregnant or breastfeeding, if you are losing or gaining weight without trying, or if a child is not growing well or is very fussy about food. Ask before using salt substitutes or supplements. Seek urgent care for severe vomiting, signs of dehydration or a serious allergic reaction.

In an emergency, call your local emergency number (112 in India, 911 in the United States).

9. Conclusion

A healthy diet is adequate, balanced, moderate and varied. The main steps are to eat at least 400 g of fruit and vegetables a day, to favour whole grains and pulses, to keep free sugars, saturated fat, trans fat and salt within WHO limits, and to cook in simple ways. These habits help protect against long-term disease. Your doctor or dietitian can fit this advice to your own health and culture.