For endurance sports, slow-release carbohydrates such as bananas, avocados, wholegrains and muesli are the most important fuel. But endurance exercise switches off the muscle-building gene. If weight loss is your aim, exercise will help you burn more calories, even once you have finished. However, that doesn't mean running or cycling on an empty stomach. 'You need fuel to give your body energy for the exercise,' says sports scientist Joanna Hall. 'Eat carbohydrate-rich foods before and after your workout. The activity speeds metabolism and aids weight loss. Endurance sports such as cycling or running are best for weight loss as they tone muscles without adding bulk.'
If athletic performance is important, eat within two hours of exercising so that any carbohydrate is used to refill stores of glycogen, a type of starch, stored in the liver as a source of energy.
If you exercise regularly, think about getting a good supply of antioxidants from food or drinks - and remember, the more intense your workout, the more antioxidants you should consume. Vitamins A, C and E, zinc, selenium and Omega 3 fatty acids are powerful antioxidants that protect the cells against damage caused by free radicals. These are formed when oxygen is liberated during certain biological processes. If they are not mopped up by antioxidants and removed from the body they can lead to cell damage and degenerative diseases. 'Exercise speeds up the metabolism and increases the rate of oxidation in the body,' says nutritionist Patrick Holford. 'Oxidation is the equivalent of a car rusting - it is a damaging process that prematurely ages tissue. Antioxidants prevent this process and can reduce the harm it does.'
Good hydration is vital. 'Just 2 per cent dehydration can reduce performance by 10 per cent,' says Joanna Hall. However, stop drinking liquids when you feel satiated as too much water can strain the body just as much as not having enough.
Aim: Liquid energy replacement is more valuable than food during a long cycle ride - the body isn't moving much and liquid is easier to digest.
Before: Eat a banana spread on two slices of wholemeal toast to give you a high-energy boost 30 minutes before intense exercise. For a long ride, make sure you eat a snack containing protein such as a croissant with ham and cheese as this will give you more stamina, plus a fruit smoothie diluted with 50 per cent water.
During: Drink water or a sports drink regularly to prevent dehydration.
After: Balance your carbohydrates and protein equally. The carbs will replenish your body with energy for your next workout while the protein will help your muscle fibres recover after a long ride. Try a bean casserole with chicken; tuna with a jacket potato or bowl of pasta and tomato salad. Two cups of green or white tea will hydrate you and give your body vital antioxidants to aid recovery.