How do i gain weight and build some muscles. i do eat a lot of healthy food but it doesn't seem to work?

Exercises: You need to also be exercising with weight resistance training, focusing on the specific areas you want to build. Finding and working with a physical trainer may help you create an exercise program that will get you to your goal. You also need to be consuming more protein that can turn into those muscles as you work.

Resistance training: In order to gain muscle weight you have to challenge your muscles. Lifting weights is a good way to challenge your muscles to grow. You would need to take in more calories than you need based on your age and weight in order to gain weight if you are lifting. You would also need at least 1gram per kilogram of body weight of protein to help build new muscle.