Personally I don't think that Christie Brinkley is a realistic anything for anyone. She is exceptionally beautiful, has a lovely smile, and she's just an overall attractive human being with amazing hair. She's also very wealthy and has the means to have personal chefs, trainers, stylists, and assistants, although they certainly only enhance the natural beauty that she has. I could have a million chefs and trainers and I'd never even remotely resemble her.
So, no, that's not the image to shoot for.
We ordinary mortals who have kids, who do laundry, who shop and make meals, who have jobs, who mop floors, who clean up spills, who pay bills, should have realistic goals.
We should be healthy. We should try to eat real food, not processed foods. In my opinion, we don't have to rule out any one food (except in the case of actual allergies or medical conditions of course), such as sugar or carbs. However, sugar has its place, like in the occasional dessert, not in seasoning packets intended for tacos and salad dressings, and soups, and convenience suppers, and boxed mixes, and flavored waters. Carbs have their place, like in sprouted grain breads, brown rice, and whole grain foods. The problem is when someone has a toaster pastry or waffle for breakfast, a sandwich for lunch, and a dinner that includes corn bread or dumplings or some casserole topped with biscuits.
A healthy weight, some exercise like walking, an appropriate body fat measurement, a good attitude towards food as fuel not emotional support, and the knowledge that pregnancy and breastfeeding and child-rearing and aging inevitably cause changes - changes that aren't a source of shame but a source of joy - are what we should be pursuing.