Thanks for asking me this question.
For gaining your weight you have to take healthy diet. For fast increase your weight by eat egg in your breakfast. One egg per day not more than that.
In breakfast take whole milk with banana.
In lunch eat green leaf vegetables like spinach, broccoli etc .Sprout can eat in diet.Multigrain Roti with soyabeen can eat.Small amount rice is use in lunch also.
In dinner eat milk, slad that full of colorful vegetables .Peanuts butter can use in situ or bread.
Drink more water per day.it help you to glow a skin.
Do
yoga every day and take fresh air.
Avoid junk food and oily foods.
Eat fresh fruits like Apple ,straberry etc.
vitamin A Helpful to increse your skin glow.
Carrot,Apple full of viamine A.
Take a juice if watermelon,peach juice.
Wish you a good health.
Thanks.