When you're actually working out a lot, you need carbs ... especially starchy, long-lasting, slow-absorbing carbs like rice.

And not just to have energy to burn during your workout, either. Rebuilding muscle requires protein to supply the building blocks, yes, but it also requires energy to assemble those building blocks together. Carbs are the healthiest, most efficient way to supply that energy.

A diet tuned for a rigorous workout regimen needs both protein and carbs.

Edit: and before anybody takes this the wrong way. No, your 30 minutes per week 'jogging' on a treadmill does not count as a 'rigorous workout regimen', and three donuts washed down by an XL caramel latte is way too much carbs, and not the best kind of carbs. This is only for people working out intensely, as in athletic training. It's also with the assumption that you're mainly working for muscle gain, not weight loss.