You were underweight before and she's worried about you getting "fat"? Wow. I don't think she's the best friend.
Anyways, you can take her for a ride to show her how hard it is...or tell her that you don't care what her opinions are of your weight, that being underweight can also be unhealthy, and that if she has any further opinions about you getting "fat" she can kindly go home with them.
Sorry, but I'm touchy about this subject and I just can't believe a friend would say that unless you were becoming overweight or obese. My friends have complimented me on my weight loss and have helped me get fit and healthy. Your friend should be happy that you gained weight.
Honestly, I don't take anything people say seriously (Well, things like that.. You know what I mean!) so I'm not worried about it. I'm very proud to have gained this weight, and people just aren't used to seeing me healthy. So if anything, I took it as a compliment.. But at the same time, I was shocked that a person could even say that! I understand honesty, but that was almost stupidity.. Which I hate to say. :( But really, I couldn't imagine saying that to a person! It just... shocks me..
I'd ditch her as a friend for sure, but you see -- Her grandma is my grandma's friend, and her mom is my mom's friend.. So I have to see her often. Better to just pretend to get along.
When I get my other horse dropped off to my house, I'll take her on a trail ride -- After about a half hour of arena work, and her learning the basics. Oh, and grooming beforehand. We'll go on EVERY SINGLE TRAIL, including the unshaded ones, LOL! I'll also have her hose whichever horse she rides afterwards.
I'm not out to make it a punishment really, but more to teach her. :)
But yes, I'm 5'8" and 108, now almost 120. I was on a long break from riding, and when I got back into it, I gained weight, I'm happy, I don't pace around the house doing nothing.. It's amazing what a hobby can do for a person! I thank God and the people around me for making my life amazing everyday. (Including the HF members!)