How do I become heavier/fatter?

Take muscle milk, taste like chocolate milk. Or they sell this powder in health stores called mass powder, you mix it with food, and its like 900 calories per tsp, so you will get heavier

 

eat foods with higher fat content? avacados?

 

Try taking protein powder/ eat more meat and such.

 

Dont take creatine, its bad. take whey protein