Question: how to gain weight fast by food?
Answer: Homemade Protein Smoothies. Drinking homemade protein smoothies can be a highly nutritious and quick way to gain weight. ... 
Milk. Milk has been used as a weight gainer or muscle builder for decades ( 1 ). ... 
Rice. ... 
Nuts and Nut Butters. ... 
Red Meats. ... 
Potatoes and Starches. ... 
Salmon and Oily Fish. ... 
Protein Supplements.