The only cat in my household who is free-fed is Ginger, who is very old. The rest get half-an-hour in the morning and two half-hour sessions in the evening to eat what they need. Yes, they get hungry, but they are healthy adult cats and it won't hurt them; I actually believe it's best for them. I use separate rooms also but sometimes have to simply stand guard - a good job they understand the word "no"! In a household of 19 cats, I feed 8 different diets.