Hello! I have a friend who wants to gain weight as she keeps losing and is smaller than she'd like to be. Her doctor says she's fine that she just has a "great metabolism."
I thought that maybe someone here would know of some herbs or supplements that have been found to increase appetite?

I think zinc is supposed to help increase appetite. But what I recommend is to eat small meals frequently - smoothies are a great way to pack in some calories - add coconut milk, nut or seed butter, tofu, yogurt, bananas, etc.

Happened to me recently too. I started "snacking" on WHOLE MILK yogurt (Maple Syrup flavored - yum) thoughout the day - the protein kept my blood sugar stable, the fat allowed me to gain a few pounds, and the maple syrup and cream were oh so good to my tastebuds!