Diet and nutrition

A balanced diet is essential for optimum performance in sporting activities. Top perfromers place huge demands on thier bodies during both training and competition so thier diet must meet energy requirements as well as provide nutrients for growth and repair. 

• Simple carbohydrates - found in fruits and easily digested.
• Complex carbohydrates - found in nearly all plant based foods and take longer for the body to digest. 

They are the main fuel source for the body and is converted into glucose and then glycogen in the muscles. Foods with a low 'glycaemic index' (release rate) cause a slower more sustained release so glucose supply is maintained. Whereas foods with a high 'glycaemic index' cause a short and rapid spike but is not maintained.

Low release rate = 3-4 hours before, High release rate = 1-2 hours before. Can be used for low intensity as slow release sustains energy and then quick rlease can be use for high intensity anaerobic events like 200m due to quick spike in energy. 

Saturated fats msotly come from animal sources, where over-consumption leads to; weight gain affecting levels of staminia, limit flexibility and lead to problems such as coronary heart disease and high blood pressure.

Too much low-density lipoproteins (LDL) leads to a build up of fatty deposits in the arteries negativelt affecting blood flow whereas HDL takes cholestrol away lowerring risk of heart disease.

Trans-fats are mostly made from insutrial process that aids in increasing the shelf-life of items. They can also lead to high levels of blood cholestrol, where we should consume no more than 5g a day.

Unsaturated fats can be used to replace saturated and trans fats as an important main energy source. Yet, they can only be used for low intensity as they require a wide availiabilty of oxygen to be broken down. (marathon runner afer carbohydrate stores are used up as low intensity means availiable oxygen). 

Proteins - made up of amino acids and are important for muscle growth and repair to make enzymes, hormones and haemoglobin. A minor energy source, used by power atheletes who need to grow and develop muscle.

Can be used when fat and glucose stores are low; meat, fish and eggs are good sources. 

Minerals - assist in bodily functions, for example calcium is important for strong bones and teeth an iron helps form the haemoglobin -> aids in oxygen transportation and can increase staminia levels.

They are dissolved in your body as electrolytes. Two functions include facilitating the transmission of nerve impulese and enable effective muscles contraction. Good sources include, eggs, vegetables, fruits and nuts.

Fibre - slows down the time taken to digest foods that can lead to a more sustained release of energy. Dietary fibre causes bulk in the small intestine hlping to prevent constipation and digestion.

-Fat-soluble vitamins - A,D,E, K - found in fatty foods and animal products, stored in the body for later use in the liver and fatty tissue.

-Water-soluble vitamins - Bs and C -not stored in the body so need to be taken daily, excessive consumption will not reap benefits as additionals are excreted through urine. 

• C - Green fruit and veg - protects cells/keeps healthy -helps maintence of bones and connective tissue e.g ligaments.
• D - skin exposed to sunlight - role in absorption of calcium, keeping bones healthy.
• B1 - egg and red meat - works with other Bs to break down food and release energy - keeps nervous system healthy.
• B2 - dairy, vegetables, egg - works with Bs to break down food and release energy - keeps eyes, skin and nervous system healthy. 
• B6 - meat, fish eggs - helps form haemoglobin - helps body use and store energy.
• B12 - red meat, fish and dairy - makes red blood cells - releases energy from food. 

Water constitutes 60% of a person's weight and transports hormones, nutrients and waste products around the body. 

Water helps regulate temperature and keeps you from overheating. Water is lost during sweat which can lead to dehydration. 

• As a result;
• blood viscosity increases reducing blood flow to the working muscles.
• reduced sweating to prevent water loss -> increase in core temperature.
• muscle fatigue and headaches.
• reduction in the exchange of waste products.
• decreased performance through decreased reaction time and decision making. 

Sports drinks like Lucozade can boost glucose before a competition, where water will rehydrate you during competition. 

The body's preferred fuel is muscle glycogen, where if breakdown exceeds replacement then stores get depleted. This results in fatigue and the ability to maintain duration and intensity. 

Research suggets endurance athletes of 6-10 grams of carbohydrate per kilogram. 

Some endurance athletes their diet to maximise aerobic energy production. Glycogen loading, six days before an important competition a performer eats a protein heavy diet for 3 days and does high intensity exercise . The followed by three days of a high carbohydrates and some light training. 

• Positive effects:
• Increased glycogen storage / delays fatigue / increase endurance. 
• Negative effects:
• Loading phase - water retention, weight increase and heavy legs.
• Depletion phase - irritability and lack of energy. 

A supplement used to increase the amount of phosphocreatine stored in the muscles as fuel for the ATP-PC system. -> Allowing the system to last longer. 

Athletes in explosive events are more likley to reap the benefits as they can perform at a high intensity for longer. 

• Positive effects:
• Aims to provide energy through ATP. 
• Replenishes phosphocreatine stores.
• Allows the ATP-PC system to last longer 
• Improves muscle mass. 
• Negative effects: 
• Possible-side effects - muscle cramps, diarrohea, water retention, bloating and vomiting.
• Hinders aerobic performance.
• Mixed evidence to show benefits.

An antacid and can increase the buffering ability of blood so it can neutralise the negative effects of lactic acid and hydrogen ions that are produced during high intensity activity. 

It reduces the acidity within muscle cells in order to delay fatigue, allowing the performer to perform at a high intensity for longer. Athletes who use the lactic acid system in their events such as the 400m or 400m rowing. 

• Positive effects:
• Reduces acidity 
• Delays fatigue.
• Increases the buffering capacity of the blood.
• Negative effects:
• Possible side-effects - vomiting, cramping, diahorrea and bloating. 

Caffeine is a stimulant so it can increase mental alertness and reduce fatigue. It is thught to improve the mobility of fatty acids in the body, preserving glycogen stores. 

It is used by endurance performers who predominantly use the aerobic system since fats are the preferred fuel for long duration, low intensity exercise. 

Studies show 3mg of caffeine per kg of body weight = biggest improvement in sporting activity. 

• Positive effects:
• Stimulant - increased mental awareness + reduce effects of fatigue. 
• Allows fats to be used as an energy source preserving glycogen stores. 
• Imrpoves reaction time + decision making.
• Negative effects:
• Loss of fine control + possible side effects - dehydration (acts as a diuretic), insomnia, irregular heartbeat and cramps.
  
• Against rules of most sports.