I excerise but i don't lose weight. why?!

Cut carbs: You also need to watch what you eat. Cut down white carbs and increase vegetables, protein and whole grains.

Look at the calories: One should choose an exercise he or she really enjoys. Any form of exercise burns calories, so if one does not eat or drink more calories than he is using during his exercise, then his body will burn up fat as fuel. However, if a person drinks a large orange juice (about 300 calories) while exercising, and exercises away only 200 calories, he will still get fatter even though he is exercising.