most people think that gaining weight is a nightmare but to some gaining weight is something that they really need. Here's some tip:

a) to lose weight cut down on your daily calory intake a.k.a reduce food consumption and increase physical activities

b) to gain weight increase your caloric intake or increase your meal,start snacking and excercise to keep up a better appetite

Gud luck!!
Diet plays an important role in our lives weather we want to lose or gain weight.i've posted 2 videos that teach both building and shedding weight.Have fun learning and exploring

Fast Weight Loss Diet - Lose 14lb in 5 days