Hi. Welcome to Health care magic. Thank you for posting your question. I can understand that you have recovered from meningitis . Itis goodto know that you have quit smoking. Let me help you out. To gain weight, you need to eat more calories than your body uses each day. You need to do this regularly. It s not enough just to have occasional extra snacks Gradual weight gain is always advisable. An increase in 500 kcal per day can result in increasing the body weight by 0.5 kgs per week. Eat plenty of healthy fats. Eat your egg yolks, meat with animal fat, coconut oil, and other healthy fats. Increase caloric intake - of the healthy kind ofcourse. So those bananas count well here. Chew the food properly to improve digestion. Keep a track of your weight gain as this is essential; it is healthy to increase approximately 5 to 6 kgs weight per month. The right combination of healthy food, exercise, right breathing, rest and sleep go a long way in a happier and healthier you. Write back to us. Regards.