Hi there, I am not Cathe but wanted you to get some sort of response. Cathe doesn't talk about her diet too often. She did post a response to a diet question last month or so on this board that may help. Maybe try doing a search for "diet". You'll have a ton to scroll through but you may find what you are looking for.
I do not believe she follows a particular "diet" but she does eat clean and allows herself the occassional treat. To look like Cathe, it is about clean eating. We'd all love to hear she eats nothing but cheese and crackers, ho ho's, ice cream and hot fudge sundaes but that is no where near reality.
Actually, now that I think about it, she did post a sample daily menu and I think it consisted of oatmeal, egg whites, fruit, chicken salads with fruit, Chicken and veggies. I have HEARD she uses Isopure protein powder in a pinch...so I have heard.
I know you want to hear from Cathe. Please understand how busy she is. If you go over to the "Open Discussion" forum to dicuss diet, you will get a flood of responses from woman just as gorgeous as Cathe.
Hope this helps some!