I am a 26 year old guy.my height is 5 feet 7 inches and yet weight is only 57 kgs.my diet is pretty decent. suggest me ways to gain weight.

Added fats: Put olive oil or butter or coconut oil on everything you eat. Do resistance training to build muscle.

Eat healthy foods: high in calories. Eat 6 meals /day. Work on strength training to build large muscle groups. Work out w heavier weights w fewer repetitions. Sleep at least 8 - 9 hrs/night. Hydrate well w water. Foods to help w weight gain: almonds, cashews, pecans, sunflower seeds, flax seeds, walnuts, hummus, avocados, granola, trail mix, dried fruits, protein shakes & bars, lean meats, poultry, fish, smoothies