How to lose 20 pounds in a month?

i ride my exercise bike every morning and night. and bench press every other day. and drink nothing but water. and i eat alot of fruit and vegetable. but a friend said fruits have Lot of carbohydrates i should eat alot of lean meats. what should i do? if you want to know why i want to lose 20 pounds in a month is for football. im 6"5 340 pounds in high school i figure i give it a try. but i dont want to go to pratice so out of shape i cant run for 5 min.