I want to gain weight, i eat a lot of calories food but still i cant gain weight, no physical activities are done?

Unable gain weight: Hi, It could be just your genetics but it's worth checking your Thyroid hormones, if you have a hyper-function thyroid you cannot gain weight but you should have other symptoms like diarrhea, palpitation, dry skin, being hot all the time. Exercising can help you gain muscle mass and therefore gain weight.

You need exercise!: To gain weight, eat more calories than you burn using healthy whole food sources like fruits, vegetables, whole grains, and beans/nuts. You will be getting plenty of protein if you eat a variety of vegetables and legumes. You will of course need to train hard and get enough rest to recover between workouts. Don't waste money on supplements. You do not need them if you are getting quality food.