Diet is the most bioindividual thing on earth. What works for CD, may not work for me or you. Doesn’t mean it has to be strict, but whereas something like sweet potatoes may never agree with me, might agree with CD, and vice versa on other foods.
I’d never expect to maintain any sort of decent health on a SAD diet. It’s not so much the food, but the food quality. Rancid omega 6 PUFAs, trans fats, MSG, and industrialized meat equal shit health for anyone, not just PFS folks.