Pick my skin and eat it?

I have calluses on the bottom of my feet and rough hands with rough patches of skin. When the callous grows back, I pick it off. Then I eat it. Yeah I eat the skin. The main places I do it is palm side up, the middle part of the thumb and top crease where the top third of index and middle finger meet the second third of it. The thumb is down to the fourth layer of skin. My second layer is hardened like the first layer, the third layer is like my second layer now, but doesn't hurt and the fourth layer doesn't hurt either. The callous on the bottom of my big toes I peel off and eat. So what is it. Is it normal???