I, too have lost weight since getting horses - nearly enough to be comfortable that I'm not breaking my horse's back when I ride. As soon as she comes off of "maternity leave," I plan to start some light riding. The weight I've lost is entirely without dieting - it's just from exercise alone!
My youngest daughter is bi-polar. Her horses are her life-savers. She can calm down around them in a way that she can't around people. She can tell them anything without feeling like she's being judged for how she feels. She has also learned (or at least she's in the process of learning) to control her stress levels. Her new little mare is very high strung and spooky - she is impossible to handle if daughter's stress level is very high at all - she seems to sense it and gets stressed out herself, which stresses daughter even more, which stresses mare even more... and the cycle is not a good thing. Daughter is learning to break the cycle by forcing herself to calm down. It's even starting to work on her kids!