Everyone needs to exercise to keep healthy and experts recommend at least 30 minutes of physical activity a day. Teens who are moderately active can get all the nutrients they need by eating a healthy balanced diet, however teen athletes will need to eat and drink more than their less active friends. Nutrition is the key to unlocking a teen athlete's full potential. If they don't eat enough, their bodies are more likely to break down muscles than build them up. Apart from eating a balanced diet which provides enough calories for energy and growth, active teenagers need plenty of water. Water works When you're exercising, your body temperature goes up and you sweat. As sweat evaporates, your skin and the blood under your skin cools down. Cooler blood flowing through your body helps protect you from overheating. However, if you lose too much water this way and don't replace it by drinking, you can get dehydrated. Dehydration can affect your strength and endurance; you're also more likely to get heat exhaustion and heat stroke if you're dehydrated. Drink before, during, and after exercising. Drink water every fifteen minutes during activity, even if you don't feel thirsty, as if you wait too long, you may already be dehydrated. Water is the best choice although sports drinks can benefit some athletes. Sports drinks contain sugar and salts (on the label, it will say 'electrolytes'). These can help athletes make up for the use of energy and the loss of salt through sweat from doing activity that lasts for more than an hour, especially in hot weather. Protein pack Teen athletes need slightly more protein than regular teens, but most can get more than enough protein from a normal diet. It's a myth that athletes need more protein to build big and strong muscles. Muscle growth comes from regular training. Carbohydrate counts Carbohydrates are the best source of fuel for everyday life, as well as physical exercise by athletes. Sports dietitians advise people to choose starchy carbohydrate foods such as rice, sweet potatoes, pasta, bread, baked potatoes, fruits, vegetables, peas, beans and lentils because these provide both long-lasting energy that athletes need to perform and nutrients they need to be healthy. Although eating sweets or other sugary snacks just before exercising or competition can give athletes a quick burst of energy, they may run out of energy before they've finished their work out. Eating to compete Foods you've eaten over the past few days will provide you with most of the energy you need on competition day. Watch what you eat in the hours before the event. Try to eat two to four hours before you compete, and choose something that's easy to digest such as a chicken sandwich or a bowl of cereal with low fat milk. Drink 500ml of water and, an hour before the event, drink a fruit smoothie or sports drink as it will help to keep you properly hydrated.