These are tips for gaining weight:
1- Eat and eat often. While everyone should abide by this rule, it is especially true for those who are trying to gain weight. Eating often means eating five to six small meals a day and packing in those nutrients.
This doesn't mean eating junk food and sugars, it means lots of protein and carbs.
2- Eat the right kind of fats. You want a bigger, healthier looking body; not a thin frame with a bit of a paunch. Maximise the avocados, dairy products, nuts (including peanut butter), and meats; stay away from ice cream, fries and fatty junk foods.
3- Go high-protein. Though it's a myth that protein builds muscle,Protein-rich foods include meat, cheese, milk, fish, and eggs. For vegetarians, protein can be found in soy products such as tofu as well as in combinations of foods, such as rice or corn with beans.
4- Layer on the carbs. Though they get a bad rap, carbs, too, help build muscle and facilitate all of your vital functions, brown rice, pasta, potatoes and whole grains fall into the approved category.
5- Snack at night.
6- Exercise to gain weight, and gain muscles and after workout eat a protein meal to benefit and have bigger muscles.