Things need detailed information about your meals and nutrition options and lifestyle then we can discuss things further and suggest anything choose direct consultation for proper guidance and help.

Hello user See, you will not gain until the cause of underweight is not treated. There are many reason of being underweight . Improper liver functions . Endocrine imbalance ( diabetes/ thyroid) . IBS . PCOS /PCOD . Gastrointestinal problems . Tuberculosis . Improper dietary diet . Vitamins and minerals deficiency .Eating disorders . Improper sleep .Stress . Medication Many more HOW WE TREAT UNDERWEIGHT THRU DIET . Finding and Curing the cause of underweight . Treating the deficiency and symptoms cause due to underweight . Diet to get ideal weight Before prescribing any thing ,we need some health information like Vitals,health parameter, physical activity, family history, occupation, daily routine and any many.so ,if you want to contact ,please contact us thru the link below

Need more information about your sister so contact me detailed conversation through practo .

- Take regular meals - Add  carbohydrates, fats, proteins,in each meal( like in breakfast, lunch, dinner) - Take in between snacks like  dry fruits, bananas, peanuts chikki. -  increased intake of chappti or rice in a day

Yes there is a way where she can gain weight but for that she need to have a proper balance diet. I also need to know her detail recall on what all she eats. So kindly consult me on Practo online consultation.

You need a properly planned diet and exercise.