I m underweight i m also going 2 gym... iin winters i have 72 kg weight bt i loss 6 to 7 kg in ssummmers.plz help.me.... my height is 5.10 inch...age?

See Dr., then eat...: If one is truly underweight (based on height, family background, and body type), a Dr. can evaluate for a hormonal, digestive, or other disorder. If no medical cause is found, then one can add weight by eating more calories of nutritious foods, while also doing weight-training to increase muscle. Proteins: egg white, chicken breast, salmon, ... Better fats: olive oil, peanuts, almonds, tofu, ....