Hello, You are a little underweight but never mind. To gain healthy weight there are many factors to be taken care of. You should ensure that your metabolism is good. You can take digestives and liver tonics to help better digestion, metabolism and assimilation of food that you eat. Avoid constipation, take fiber in diet. If needed take laxatives to keep your bowel clean. Sleep also plays an important role in maintaining healthy weight. Take 8 hours of quality sleep. Exercise regularly to stimulate your appetite. Stay away from anxiety and stressful lifestyle. Avoid both physical and emotional stress. Take food 4-5 times a day. Take larger portions of well-cooked whole grains, fruits veggies, nuts, seeds, dry fruits. Take healthy fats that provide energy and protection. Take eggs, omega-3 rich food, avocados, butter, ghee, chocolates, banana, fiber etc. Increase calorie intake. Take superfoods. Take carbohydrates, increase more protein intake. Take meats chicken, beef, pork, and lamb; choose fattier cuts. Have tubers like potatoes, sweet potatoes, and yams. Take shakes and supplements. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K, General & Family Physician