What is the best foods for fast bodybuilding supplements?

Go to a specialist bodybuilding website (preferably with a discussion forum). You need to make your questions a bit more specific - so, for example, what's your height and weight, how long have you been training, do you have any food allergies etc. If you simply say "what's a fast way to gain weight" you will be either labelled a troll, ignored or some smartarse will post a response like "Uhhh...go to the gym, maybe?" You'll also need to set a food budget, and describe you current diet (f you are following one). Basically, the more specific you can be, the more help you will get.