Being thin is not that big problem if you are confident. ,healthy and having good immunity level.To maintain weight you need to eat healthy balance diet comprising of 3 main meals and 3 small meals including all food groups carbohydrates i. e. Cereals .good quality proteins I.e. milk products, pulses,eggs,lean meat and some fruits as well as cereals, Minerals and vitamins I.e.fruits and vegetables Good Fats and oils Sugar and jaggary Keep proper hydration Do regular physical activity for 50 mnts Keep yourself stressfree and sleep well