Diet and Nutrition

The aim of this lesson is to learn about the foods that make up a healthy balanced diet (Equivalent to UK GCSE Physical Education)

People are always talking about a balanced diet, but what does this actually mean?

A balanced diet contains all the nutrients you need, in the right amounts to keep you healthy. The best way to make sure you get this is by eating a varied diet. One that contains the following four food groups:

Meat and fish
Dairy products
Fruit and vegetables
Bread, cereals, potatoes, nuts, pulses etc

Doing this will ensure you get a mixture of Carbohydrates, Proteins and Fats.

Carbohydrates

These are our main source of energy
They can be simple carbohydrates - sugary foods like cakes and biscuits etc!
Or complex - starchy foods like potatoes, rice and pasta - we should eat more of these than simple carbs
Complex carbohydrates are broken down into simple carbs (such as glucose/fructose etc) in the stomach. Some is used for energy straight away and some is stored in the liver and muscles as glycogen
Carbohydrates should make up a total of 55% of your daily diet

Proteins

Proteins are used to help us grow and repair tissues
Proteins are found in animal products such as meat, fish, milk and eggs
They are also found in beans and lentils
Proteins are made from amino acids
Amino acids can be either essential, meaning we can't make them in the body so you must eat them in your diet
Or non-essential - meaning your body can make them
Proteins should make up 15% of your daily diet

Fats

Fats are a source of energy and also provide warmth for our bodies and protection for our vital organs
There are three types of fat:
Saturated Fatty Acids - Which are mainly found in animal fats and are usually hard at room temperature e.g. butter
Monosaturated Fatty Acids - These are usually liquid at room temperature such as oils
Polyunsaturated Fatty Acids - These are the best type of fat for you and are found in oily fish and some oils
Fats should make up 30% of your daily diet

Pie chart

We also need the following nutrients in small amounts, to stay healthy:

Vitamins

Vitamins are needed for chemical reactions and also to help our bones, skin and teeth to grow
They can be either fat soluble or water soluble
Fat soluble vitamins can be stored in the body and include:
- Vitamin A for growth and seeing in the dark! Found in vegetables, liver and eggs
- Vitamin D for strong bones, found in milk, fish and eggs
Water soluble vitamins cannot be stored in the body so we need to eat these in our diet
They include Vitamin C which you need for healthy skin, gums. This is found in fruit and vegetables

Minerals

We need them for healthy bones and teeth, as well as the growth of other tissues
Minerals include things like:
- Calcium for strong bones and teeth as well as muscle contraction. This is found in dairy products and vegetables
- Iron for haemoglobin in red blood cells. You can get iron from liver, beans and other green vegetables
They are used in many chemical reactions in the body too

Water

Water doesn't count as a nutrient, but its something your body needs
You need it in chemical reaction and for when you sweat to cool your body down
If you don't drink enough you can become dehydrated. This can affect your performance
If you drink too much you just produce extra urine to get rid of it!

Fibre

Fibre isn't really a nutrient either, but you definitely need it in your diet
It keeps your digestive system working properly
You can find it in fruit and vegetables

Diet and Sport

As well as thinking about having a balanced diet and getting all of the nutrients your body needs on a daily basis, athletes also have to think about what foods are going to benefit their sporting performance and when they should eat to fit around training and competitions.

Athletes involved in different sports will have very different diets. For example, a weight lifter will eat a diet high in protein to help their muscles grow. An endurance athlete will have a diet high in carbohydrates to store their muscles with glycogen for energy.

When building up to a competition, some athletes will also use a technique called carbo-loading, where they eat a lot of carbohydrate rich foods in the run up to the event. This ensures their muscles and liver are stocked up with glycogen so they have plenty of energy.

During an activity you shouldn't eat anything as your digestive system may not be able to cope as the blood is being diverted to your working muscles, not your stomach! You should always make sure you keep drinking throughout exercise though, to replace the fluid you are loosing through sweat and breathing out more water vapor.

It is important to eat following exercise to replenish your energy stores. Don't eat straight away though, give your body and hour or two to recover. In this time you should continue to take on fluid to prevent dehydration.

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