Hi Mitch Welcome to HCM .I have gone through your details and according to my opinion weight gain or weight loss depends upon body BMR ( basal metabolic rate) and other factors like genetic,hormonal imbalance,diet,stress,lifestyle etc.As you want to gain weight here I am suggesting few effective remedies which you have to follow like Have 1 tbsp chyavanprash daily in morning. Have banana with a glass of milk daily. If you are non vegetarian you can opt for 1 egg with a glass of milk daily. Soak few almonds,raisins,dates overnight and consume in the morning. Have 1 tbsp ashwagandha and 1 tbsp shatavari churn with milk. Have high calorie food like ghee,butter,cheese,paneer ,rice,potato in your diet. Consume fruits such as mango,litchi,banana,grapes daily. Herbal medicines are also effective like kushmandavaleha,shatavari,ashwagandha,bala,yastimadhu. Practise yoga and pranayam for weight gain like shavasan,yoga nidra,sarvangasan,bhujangasan Full body massage with medicated oils is recommended. Be positive and stay away from stress is a good way to gain weight. In the last I would like you to get your thyroid profile checked to rule out endocrinal problem if any. I hope this answer is useful to you. Wish you good health Mitch. Take care Dr.Pallavi