There are different types of weight: Muscle, fat, bonemass and water. I can assume you obviously want bonemass and muscle, for some people even fat can be beneficial. To gain muscle just workout bro, to gain bonemass just abuse AAS and HGH, to gain fat eat carbs and fats together and to increase water (only benefit i can see is when you are out in the sun alot so you arent dehydrated) is to obviously drink it and eat carbs