How can I gain 5 kg in a month?

Eat more omega 3 fatty acid sources like salmon and tuna. Try Flax seed and walnuts. Poultry, nuts, seeds, legumes, chickpeas, kidney beans, peanut butter, omelets, whole grain products like cereals, rice, pasta. Bagels, granola and cornbread. Veggies like avocados, olivves, potatoes, peas, corn, squash. Fruits like canned fruit in syrup, dried fruit and fruit nectar drinks. Use a protein powder or drink like ensure, or instant breakfast drink with each meal. Use multivitamin and minerals, every day. Use milk instead of water, incereals, soups, sauces. Mix chopped beef, wheat germ, nuts, beans, or cheese in casseroles, pastas, rice and side dishes. Add at least 300-350 calories a day to your normal intake, adding any of the above to your meals will help, and use larger portion then you normally eat.

Eat too much. You will not believe it but I am gaining 1KG everyday. Eat 5 times a day and eat till food reaches your neck and you are about to vomit.