Hmmmmm .... I have never seen her exert too much energy! But you never know! I was also considering just shaving off some of the door -- so that it sat at 1m high ... BAH maybe the screen door option is best. I hadn't even thought of food and litter issues yet either. Separating them will be a problem as well as we don't have space for a cat side and non cat side, you know? Hmmmmm ....