BIOLOGY · Stage 8 · Chapter 6: Nutrition, Health and Movement
Biology 6.4 A balanced diet — Vitamins, Minerals, Fibre and Water
5 min read 5 parts Lesson 4 of 12
Lesson summary
Biology 6.4 A balanced diet — Vitamins, Minerals, Fibre and Water — Alhussan International Academy — Biology (Stages 7–9) notes: Describe what makes a diet balanced and explain how needs differ between people and places.Constituents — the diet must contain carbohydrates, proteins…
- Common recommendations
- Proportions
- Body water
- Diet and health
- Planning a meal
- Checking a day's diet
Section 1 of 5What is a balanced diet
- Constituents
- the diet must contain carbohydrates, proteins, fats and oils, vitamins and minerals, found in many different foods.
- Balanced diet = a wide variety of foods that supply the nutrients needed in healthy proportions.
- It does not matter exactly what food is eaten if the diet is balanced.
- Common recommendations
- a balanced diet replaces the energy used by cells for the functions of life and gives the nutrients needed to grow and repair.
- Proportions
- eat lots of carbohydrates, fruit and vegetables, always some protein and small amounts of fats and oils.
- Foods such as ice cream and sweets should be occasional treats.
Section 2 of 5Differences in needs
| Person or place | Greater need | Reason |
|---|---|---|
| Cold country | More energy-rich food | More energy is lost as heat |
| Hot country | More water | Water is lost in sweat |
| Manual worker or athlete | More carbohydrate and energy | Muscles use more energy |
| Growing child or young person | More protein and calcium | Growth of tissues and bones |
- Variation
- nutritional requirements vary between countries and people, and needs change through life.
- Principle
- variety and proportion stay the same, but quantities change.
Section 3 of 5Water
- Body water
- the body is almost 70% water.
- Losses
- water is lost all the time by exhaling, sweating, urine, tears and faeces, and it must be replaced by drinking.
- Amount
- everyone needs at least a litre of water every day.
- People in hot countries need more because they sweat more to keep cool.
Section 4 of 5Fibre
- Fibre
- an important part of a healthy diet, but not a nutrient.
- It is made of large molecules the body cannot digest, often cellulose from plant cell walls.
- It gives bulk that helps move food steadily through the digestive system and prevents constipation.
- Health
- a high-fibre diet helps protect against heart disease and some cancers.
- World data suggest that plenty of fibre reduces the risk of dying from colon cancer.
- Sources
- beans, pulses, whole grains, fruit and vegetables.
- Diet and health
- diet has a big effect on growth, development and health.
Section 5 of 5Planning and checking a balanced diet
- Planning a meal
- estimate energy needs from age and activity,
- then add a starchy base, a protein portion, plenty of vegetables and fruit, a little oil and water to drink.
- Checking a day's diet
- list the foods and tick the nutrient groups they supply.
- All groups must be present, energy must match activity, and there must be enough water and fibre.
- If a group is missing, add a food that fills the gap, such as beans for protein or an orange for vitamin C.
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