Eating to Gain
There are two requisites for gaining weight: eat more and work out. Eating several times a day works for many people, but not everybody. The important thing is to get a lot of calories without feeling stuffed. Try adding a little olive oil to salads and veggies, and drink fruit juice instead of water sometimes. Get a little calorie counter at the bookstore and go for the options that are more calorie dense. Make sure you work your whole body during the week, with several sets of 8-12 reps. It's important to eat within half an hour of working out. Try for at least 300 calories, with a three-to-one ratio carbs to protein.