Best way to stay fit in vet school - become a fourth year student. I spend most of my day on my feet, the hours are long depending on the rotation (Current rotation averages about 9/day which isn't bad...last rotation averaged 15/day) and I don't always have time to eat on a normal schedule let alone snack all the time.
I get to practice yoga and pilates while holding x-ray plates in various contorted positions underneath a horse. Weight training is lifting giant dogs and holding horse feet or xray plates in the air for 100 different xray views. Stamina is running from one part of the hospital to the other while wearing a lead gown. All in all, I've lost about 5 pounds just in the past month.