Hi thanks for posting your query.I have gone through your details.As you have mentioned that your thyroid profile is normal and you want to gain weight ,weight gain or weight loss depends upon body BMR( basal metabolic rate). So you have to keep your metabolism good in order to gain weight..To boost your metabolism you have to follow well balanced diet,exercises,yoga and meditation. Here I am giving you effective diet tips to gain weight Have 1 tbsp chyavanprash daily in the morning. Have banana or banana with milk daily. If you are non veg you can have mixture of 1 egg with lukewarm milk daily.Its one of the effective remedy for gainingweight. Boil 1 glass of milk with almonds,dates,raisins and drink. Have a high calorie diet like more cheese,ghee,butter,peanut butter,eggs in your diet. You can have fruits like banana,mango ,litchi ,grapes in your diet. Eat 4-5 small meals in a day. Boil 1 tbsp ashwagandha powder with 1 tbsp shatavari powder in a glass of milk and drink daily. Take a nap after a noon meal as it increases kapha in the body. Boost your metabolism by walking daily for 30 minutes. Practise effective as an as daily such as sarvangasan,shavasan,yoga nidra,bhujangasan,pavanmuktasan daily. Effective herbs like ashwagandha,shatavari,kushmanda,yastimadhu can be consumed daily. Massage full body with medicated bala oil,til oil or olive oil daily or thrice a week. I hope this answer is useful.In case of further query I am happy to help you. Best wishes for good health! Regards Dr.Pallavi