what kind of food do you suggest ?!

peanut butter and banana pita- it's an amazing thing to eat.
When you've spread the PB and banana slices inside the pita- toast it.

Eat a lot of nuts, avocado, coconut, peanut butter, cashews, walnuts, cheese and full fat yoghurt.
Eat whole grain bread- not the white stuff- it has to be 100% wholewheat, and eat it with HUMMOUS- a fantastic chickpea spread. Toast the bread, or sprread the hummous on wholewheat pita and add cream cheese. IT's a very healthy food. No animal fats, just pute plant oils, full of good nutirents.

Eat NO PROCESSED foods- only whole foods.

Peanut butter
Hummous, Cream cheese
bananas
walnuts, peanuts, almonds, cashews, brazil nuts, pecans
whole wheat bread and pasta.
avocado, coconut.
soymilk, soybeans, they're healthier than cows milk.

All these above you can eat for maximum health/

Lots of protein and healthy fats, such as chicken, pork and turkey (light colored meats without grease and fat). Eggs are a great source of protein and you can eat them in hundreds of ways that are non-greasy (hard-boiled, egg salad, mixed in rice). Also, lots of green veggies. The downfall to greens and fruits is the fiber content- fiber causes you to go number 2 more often, so don't overdo it on the veggies.

Then: drink 3 Boost Protein nutritional supplements a day (after each meal).

Doing this the healthy way (natural fruits, nuts, veggies, and non-greasy meat), you can gain a pund or more a week if you have a 4000 calorie/day diet everyday.

Good luck, it has worked for me.

Oh, and also, muscle weighs more than fat and will keep your energy levels up, so make sure to incorporate some excercise to avoid muffin top syndrome, and have a healthy, shapely body.

I wouldn't go around eating unhealthy foods to gain weight, i'd just eat MORE of the good stuff. Just, say you're having dinner, have a little more than you normally would.

Don't go eating unhealthy foods like Maccas just to gain weight, it's dangerous.

I don't think you want to get fatter, rather than to gain more muscle mass. Increase your activity level and maintain your intake of high quality calories.

Drink lots of fruit smoothies, because fruit has a lot of natural calories.