NO ONE likes to be stuck at their desk all day. I think this is just cruel and controlling! I personally would go crazy if I was asked to eat my homemade lunch at my desk. In the past I have always needed to LEAVE MY DESK several times a day or I would lose it! I would see if your boss will compromise and let you still be in contact but ask if you can go and sit outdoors nearby or perhaps just move to a different part of the office for at least a different environment. See what he says.