How to loose weight by summer?

What does that mean? Did you mean how to lose weight during the summer? Depends on how hot the summer is at the place where you stay. If you stay at a hot and humid place like I do then you can lose weight if you engage In limited amount of activity. Make sure that you play some sport or the other everyday during the summer and you will notice that you have lost weight in a matter of weeks. But, at the same time you must compensate this with plenty of juices and water, otherwise your body will become too weak.