I had a big personal loss 2 weeks before I started intern year. I had a hard time even keeping food down, cried myself sick a few times.
Breakfast was a latte. Lunch came from a very nice, healthy cafeteria. Sushi most days. I didn't get a chance to unpack my kitchen stuff from my move, for like 4 months, so I was mostly eating a pair of microwaved poptarts for dinner, or breakfast. Takeout if I came home early enough which wasn't often.
In literally 1 month, I lost 20 lbs. 5'8, 134 lbs and curvy, to start. Ended up at 114 by first rotation end. My co-residents asked me if I had cancer. Just the cancer of residency. Swimming in my clinic clothes, no time to shop. I had to use a kitchen knife to put several new holes in my belt to hold up my pants.