Re: Really skinny wrist/body
Celiac disorders also could be a factor. That is an intolerance to wheat gluten, which is in a lot of our foods. My mom was diagnosed with that a couple of years ago. Have you had an issue with anemia at all? If not, then celiac is not likely, but still one other thing to consider.
Hyperthyroidism is something else to consider if you are not holding weight.
A check up with your doc, and some tests should be enough to tell if you have some health condition behind things. If there are no underlying health conditions then you possibly just have a high metabolism. If you are an active person as well, that also helps keep the weight down.
My oldest two sons (early 20's) are both very lean, active, and can eat me out of house and home when they visit, and both are perfectly healthy. They take after me in that respect.
I am a small boned person, and was always one of the smallest, skinniest people in my school too. I was always an active person who spent a lot of time outdoors doing things, and could eat anything I wanted. I never worked out, but the activities I was usually doing was just as good as a work out. My wrists are a little over 5" around, and I am in my mid-40's. Not as active as I use to be due to some back issues that limit my activities.
Go see your doc, get a check up, and if there is nothing behind it, don't worry about it and enjoy being able to eat anything you want!