Im 27 and 108 pounds and 53. i cant gain weight at all.(genetics has a lot to do with being skinny ) what can i take to gain healthy weight?

Eat healthy foods: high in calories wi 6 meals /day. Use 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.