Mostly, yes, that is the whole focus of the Core plan. Whole grains, lean meats, fruits & veggies, no processed or frozen type dinners. There are a couple weird items that they threw in to make it easier for dieters. The one that comes to mind is you can have sugar-free, fat-free pudding made with skim milk because it is very dessert-like. However, it contains many chemicals, so I look at that as an exception to the clean eating part. You can also have certain canned soups, while homemade is better for you.
It's a great starting point for clean eating. The longer I'm on it, the more I weed out those other foods and eat cleaner. HTH!