Diet & Nutrition

Balanced Diet

A balanced diet involves taking the right amount or level of energy and nutrients that the body needs in its expenditure of energy.

A balanced diet for humans is one that contains the correct proportions of carbohydrates, fats, proteins, vitamins, minerals and water necessary to maintain good health.


Carbohydrates (50% of Diet)

  1. This macronutrient is the ‘fuel’ that provide us with energy to sustain performance.
  2. There two different types: Simple Sugars & Complex Starches.
  • Simple Sugars - These provide a quick energy source and include glucose and fructose. Examples of these are sugar, jam, confectionary and fruit juices.
  • Complex Starches - These have many sugar units and are much slower in releasing energy. Examples of these are cereal, pasta, potatoes and bread.

3. Carbohydrates are stored in the muscles and the liver as glycogen but in limited amounts that need to be replenished.

Fats (30-35% of Diet)

  1. These are also used for energy, but only when stores of carbohydrate run low. Fat provides very slowly released energy. This is important for endurance activities. The longer you work the more fat is used.
  2. Fats also help to keep the body warm and protect organs, which helps to prevent injury.
  3. There are two types of fats: Triglycerides & Fatty Acids.
  • Triglycerides are the fats which are stored in the form of body fat.
  • Fatty acids, are used mainly as a fuel for energy production. These are either Saturated Fats or Unsaturated Fats.
  • Saturated Fats are in the form of a solid, e.g. lard, and is primarily from animal sources.
  • Unsaturated Fats are in the form of liquid, e.g. vegatable oil, and comes from plant sources.

Protein (15-20% of Diet)

  1. Protein is an essential nutrient that promotes growth and repair of muscles.
  2. Proteins are also used to generate energy only when the body has exhausted its stores of carbohydrates and fats.
  3. Proteins are also needed by performers who are recovering from injury in order to repair damaged tissue.
  4. The main sources of protein are Meat, Fish & Poultry products.



  1. Vitamins contribute to the general health of an athlete.
  2. Vitamins are needed to:
  • Resisting infection and disease
  • Regulate chemical reactions in the body.


  1. Your body needs minerals to help it function. In particular minerals increase the efficiency of carrying oxygen to muscles.
  2. Minerals can be found in:
  • Calcium in milk - Calcium is essential for healthy bones and teeth.
  • Iron in meat - Iron is important for the blood cells that carry oxygen.

3. Minerals are only needed in small quantities but are vital for the body.

4. Minerals are non-caloric.


  1. Fibre is required to aid the smooth working of our digestive system.
  2. Good digestion means that your body gets all the nutrients it needs from food.
  3. Fibre can be found in food such as fruit and vegetables, as well as cereals, beans, lentils and wholemeal bread.


  1. The human body is 75% water. We need regular intake to replace the water lost through urine, sweating and breathing.
  2. When exercising the body loses even more water which can cause dehydration.
  3. Water is needed in chemical reactions that occur around the body.
  4. Water is also used as sweat to help you cool down when your body temperature rises.

Effects of Dehydration

If you do not drink enough water to replace the water that has been used or lost during exercise, you will become dehydrated. This means your body doesn't have enough water to work efficiently. This can cause:

  • Blood Thickening - This means it makes it harder for the heart to pump the blood around the body, therefore it has to work harder and beat faster. It also decreases the flow of oxygen to the muscles.
  • Increase in Body Temperature - Without enough water, the body can't sweat effectively. This can cause overheating and maybe even fainting through heat exhaustion.
  • Muscle Fatigue & Cramps
  • Slower Reactions and Poor Decision-Making - Your brian needs water to function effectively and efficiently too.

Effective Nutritional Strategies

Glycogen Loading

To ensure optimum energy supplies for aerobic exercise, one method of increasing glycogen available is through 'glycogen loading', which is also known as 'carb-loading'.

This involves:

  1. Cutting down on carbohydrates and keeping to a diet of protein and fat for three days.
  2. Light training follows, with a high-carbohydrate diet for three days leading up the the event.

This has been shown to significantly increase the stores of glycogen and helps offset fatigue.


You may lose up to one litre of water per hour during endurance exercise; therefore rehydration is essential, especially if there are also hot environment coniditions.

  • Take fluids/water before exercise to ensure your body is fully hydrated.
  • Take fluids continuously throughout exercise.
  • Small amounts at a time is often the best.

Factors To Consider With Sports Performers

Sports Performers, especially at the top level, have certain aspects to their lifestyles that should be considered when planning nutritional intake:


Ensure the timing of meals is able to fit around the training schedule and events


Ensure that there is balance in the diet, with the right proportions of food being consumed.


Ensure that there is enough fluids being consumed throughout the day.


Ensure that the diet is suitable for the demands of the sport or activity.

This means the diet should be designed to ensure the athlete has enough energy to compete in their sport.

Psychological Well-Being

If an athlete is unhappy with the diet, then even if physiologically beneficial, it could negatively affect performance because of psychological pressure.


There should be a sharing of ideas between coach/dietician and performer to agree the best strategu, depending on the individual's needs and perceptions.

Topic Test