My grandmom is 79 & trying to gain weight but cant (despite a healthy appetite) had all kinds of tests & its normal. her doctor said she should drink ensure to get lots of protein but theyre expensive. anything else she could do to gain weight?

Get the app Cronometer and track calorie intake for a day or so. Then increase calorie intake using something she likes. She is most healthy with a BMI of less than 25. Good luck.

I've had several elderly patients that I put through an extensive workup because of an unexplained weight loss if about 10 lbs & found no pathology. It's almost as if nature reset their weight. I recommend taking her to a dietician for a one time consultation. She'll be advised as to her ideal weight, how many daily calories to ingest and sample diets given and her eating habits critiqued.