Jamie Oliver, a young chef, went to the US and did a show (I do believe the 2nd season just started) about helping a school eat better. They had pizza for breakfast, high content sugared milk and other rubbish.
Not only that the children had no clue about what vegetables where when asked what a potato was for example.
Anyways my point is, get food made for you for lunch and take it with you and a small bottle of water or fresh orange juice/apple juice (has to be fresh apple, the others have huge sugar content). That way you control your calories at school.
Also the time of day you eat is very important if your serious about loosing weight. You can have the best diet in the world but if you eat at the wrong times you can put on weight. This usually consists of eating main meals or lots of food before bed (your eating but not burning it off while your sleeping) by best advice is to keep to a 3 meal a day policy with meals at breakfast around 7-8am (depending on when you wake up) lunch between 12-2pm and then dinner at 5-7pm, snacking inbetween is fine as long as your sensible with it.
Finally exercise, if you don't know your intensity levels you can roughly guess depending on how your feeling when exercising, there's formulas to work it out but it's not really need it, just search for "VO2 max" if you want to be sure. It's all about your heart rate, and you being a football player all year round I'd say you should have a pretty high standard. The key to exercise is knowing the levels you can work at. anything above 60% of your maximum heart rate is your "fat burn zone" you don't have to go anywhere higher than the 60-70% zone to burn your fat. Knowing this you can work for longer periods of time while burning fat.
Hope this helps you out and goodluck.
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