Edexcel iGCSE Biology-2.24 balanced diet- Study Notes- New Syllabus

Balanced Diet

📝 Introduction

A balanced diet = eating the right amounts of all essential nutrients so the body works properly.

It is not just about eating food – it’s about eating in correct proportions.

🔑 Main Components of a Balanced Diet

Carbohydrates

• Main source of energy.
• Examples: rice, bread, pasta, potatoes.

Proteins

• Needed for growth, repair and enzymes/hormones.
• Examples: meat, fish, beans, eggs.

Lipids (fats & oils)

• Source of energy (store more than carbs).
• Provide insulation and protect organs.
• Examples: butter, oils, nuts.

Vitamins

• Needed in small amounts for health.
• Examples: Vitamin C (healing, prevents scurvy), Vitamin D (bones).

Minerals

• Important for body functions.
• Examples: Iron (makes haemoglobin), Calcium (bones & teeth).

Water

• Makes up ~70% of body.
• Needed for transport, chemical reactions, temperature control.

Dietary Fibre

• From plant cell walls (cellulose).
• Adds bulk to food → keeps gut contents moving → prevents constipation.

📊 Balanced Diet = Correct Proportions

Nutrient	Function	Example Foods
Carbohydrates	Energy	Rice, bread, pasta
Proteins	Growth & repair	Meat, beans, fish
Lipids	Energy, insulation	Oil, butter, nuts
Vitamins	Health	Fruits, vegetables
Minerals	Body functions	Milk (Ca), red meat (Fe)
Water	Transport, reactions	Drinks, fruits
Fibre	Digestive health	Vegetables, whole grains

🎯Tips

• “Balanced” means all nutrients in correct proportion, not equal amounts.
• Deficiency = disease (Vitamin C → scurvy, Iron → anaemia, Fibre → constipation).

⚡ Quick Recap
Carbs = energy.
Protein = growth & repair.
Lipids = stored energy + insulation.
Vitamins = small amounts, health.
Minerals = strong bones, blood, etc.
Water = life medium.
Fibre = healthy digestion.