Iam very thin, weak comparing to other guys of my age. how can i gain weight as my parents are planning for marriage. even my girlfriend complaints...

Emaciated??: If you are eating healthy you need to be evaluated by a medical professional to rule out the possibility you may have an intestinal parasite or metabolic disorder.

Weight Gain: Ask your doctor for a complete physical to rule out any medical issues that may prevent weight gain. If cleared consult with an exercise physiologist who will design an exercise/nutrition plan for weigh gain and better overall health .Best.