There are some dishes where the actual flavor of rice or of couscous is essential for the dish--sushi being a prime example. But for some dishes, the rice is really more taste-neutral because the sauce overpowers whatever flavor it might have.

I was making chicken curry from scratch recently and realized that the flavor of rice is really drowned by the flavor of the curry, so there was no point blowing my carb allowance on having rice with the curry.

But, what to substitute? Mostly it had to be bland with a good texture. Any flavor would have to go well with curry.

Cauliflower, of course--it's often an ingredient in curry anyway.

If you food-process the cauliflower first, then microwave it, it comes out with a couscous-like texture that works really well!

(if you cook Cauliflower first and then grind it you get a mashed-potato-like consistency, so don't do it that way if your substituting for rice or couscous).