Well, I don't consider a flaxseed muffin a "substitute" for anything. It is real flaxseed, a real egg, real coconut oil.

I don't feel the same way about Atkins bars, which involve sugar alcohols and various chemicals I don't count as "real" food.

The low-carb instructions say, NO FLOUR PRODUCTS. So why would a flaxseed muffin be a bad choice? It isn't a "fake flour" product. It's something entirely different. And those are the choices we make.