So, eating yogurt, almonds and fish is very healthful, but these are foods associated with
losing weight, not gaining it. Just depends on what the poster is after, and so far the poster hasn't filled in any details, but again, if all the person wants is to gain weight, just eat more and focus on unhealthy food and you'll gain weight. Won't be good for you, but it should work absent something quite wrong with the digestive system or metabolism.