Balanced diet principles

Overview

This study guide provides a comprehensive overview of the principles of a balanced diet, as required by the OCR J309 specification for GCSE Food Preparation and Nutrition. A deep understanding of this topic is fundamental, as it forms the basis for many other areas of the course, from nutritional needs through life stages to the dietary causes of ill health. Examiners expect candidates to move beyond simply listing the food groups and to demonstrate a clear understanding of the physiological reasons behind dietary recommendations. This means linking specific nutrients to their functions in the body and applying the principles of the Eatwell Guide to practical scenarios, such as modifying recipes for specific target groups. Credit is awarded for precise, scientific language and the ability to justify dietary advice with clear reasoning.

The Eatwell Guide

The Eatwell Guide is the UK’s healthy eating model. It shows the proportions in which different types of foods are needed to have a well-balanced and healthy diet. It is essential that candidates can not only name the five main food groups but also explain their relative proportions and the key nutrients they provide.

The Five Food Groups

• Fruit and Vegetables: Should make up just over a third of the food we eat each day. Aim for at least five portions of a variety of fruit and veg each day. They are a vital source of vitamins, minerals, and fibre.
• Potatoes, bread, rice, pasta and other starchy carbohydrates: Should also make up just over a third of our diet. Wholegrain versions are recommended as they contain more fibre and release energy more slowly.
• Beans, pulses, fish, eggs, meat and other proteins: This group should make up about 12% of our intake. Protein is essential for growth and repair. Oily fish is particularly important for its omega-3 fatty acid content.
• Dairy and alternatives: This group makes up 8% of the diet and is a key source of calcium for bone health.
• Oils and Spreads: A small amount (1%) is needed. Unsaturated fats are healthier choices.

Energy Balance

Energy balance is the relationship between the energy we consume (Energy In) and the energy we expend (Energy Out). A consistent energy imbalance will lead to a change in body weight. Examiners will often test this concept in the context of diet-related diseases like obesity.

• Positive Energy Balance (Weight Gain): Occurs when energy intake is greater than energy expenditure.
• Negative Energy Balance (Weight Loss): Occurs when energy intake is less than energy expenditure.
• Energy Balance (Weight Maintenance): Occurs when energy intake equals energy expenditure.

Key Nutrients and Their Functions

For higher marks, candidates must link nutrients to their specific biological functions. Vague statements like ‘gives you energy’ will not receive credit. You must be specific about which nutrient provides energy and how.