Such treatments as Abhyanga (oil massage) and Shirodhara (head oil treatment) are very good in terms of stimulating metabolism, calming the nervous system and increasing the ability to absorb nutrients. Abhyanga using warm sesame or ashwagandha oil nourishes the tissues and Basti (medicated enema) is used to balance the Vata dosha (that is usually accompanied by underweight conditions). Frequent training aids in the recovery of body strength and endurance. Know more about ayurvedic weight gain (https://naturecaresayurveda.com/blogs/health-library/ayurvedic-weight-gain/)