What is a balanced diet, and how does diet and energy balance affect performance and health?
The components of a balanced diet (carbohydrates, fats, proteins, vitamins, minerals, fibre and water), the role of each, energy balance and its effect on body weight, and how diet and hydration affect sporting performance and health.
A focused answer to Eduqas GCSE PE Component 1 on diet and nutrition: the seven components of a balanced diet and their roles, the energy values of the macronutrients, energy balance and its effect on body weight, hydration, and how diet affects sporting performance and health.
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What this dot point is asking
Eduqas wants you to know the components of a balanced diet and their roles, the idea of energy balance and how it changes body weight, the importance of hydration, and how diet affects performance and health.
The components of a balanced diet
Energy balance and body weight
A performer matches their intake to their training so that their body composition suits their sport: a sprinter wants to be lean and powerful, a sumo wrestler wants high mass.
Hydration and performance
Water is lost through sweating during exercise. Dehydration thickens the blood, raises heart rate, reduces the ability to sweat and cool down, and causes early fatigue, cramp and a drop in concentration and performance. A performer should drink before, during and after exercise to stay hydrated, and replace fluid lost in long or hot sessions. Even small fluid losses measurably reduce performance, which is why hydration is examined alongside diet.
How diet affects performance and health
The right diet provides the energy to train and compete, the protein to repair muscle, and the vitamins and minerals for health (iron prevents anaemia and tiredness; calcium keeps bones strong and prevents stress fractures). A poor diet causes fatigue, slow recovery, poor body composition and, over time, ill health. Timing matters too: carbohydrate loading before endurance events and protein after strength training are common strategies, and both link diet to the principles and methods of training.
Exam-style practice questions
Practice questions written in the style of WJEC Eduqas exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Eduqas 20184 marksExplain the role of carbohydrates and proteins in the diet of a sports performer, and give a situation where each is especially important.Show worked answer →
A Component 1 nutrition question. Two marks for each nutrient (role plus a relevant situation).
Award marks for: carbohydrates are the body's main and preferred source of energy, especially for moderate-to-high-intensity exercise; they are stored as glycogen in the muscles and liver. They are especially important for an endurance performer (a marathon runner carbohydrate-loads before a race to maximise glycogen stores and delay fatigue). Proteins are needed for the growth and repair of muscle tissue and for making enzymes and hormones. They are especially important for a strength or power athlete (a weightlifter eats protein after training to repair and build muscle).
Markers reward the correct role and a sensible applied situation for each nutrient. Saying protein is the main energy source is a common error.
Eduqas 20214 marksExplain what is meant by energy balance, and describe what happens to body weight when energy intake is greater than, equal to and less than energy expenditure.Show worked answer →
A 4-mark energy-balance question. Markers reward the definition and all three outcomes.
Award marks for: energy balance is the relationship between energy taken in (from food and drink) and energy used (expended) by the body through basal metabolism and activity. When intake equals expenditure, body weight stays the same (energy balance). When intake is greater than expenditure, the surplus energy is stored, mostly as fat, so body weight increases. When intake is less than expenditure, the body uses stored energy, so body weight decreases. A performer adjusts intake to their training load to keep the body composition their sport needs.
A top answer defines energy balance and states the weight outcome for all three cases (gain, maintain, lose).
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Sources & how we know this
- Eduqas GCSE (9-1) Physical Education C550QS specification — Eduqas (2016)