White flour doesn't just rob you of fiber and protein, it also digests incredibly quickly in the body, giving you a rapid spike of energy-but one that comes crashing down just as fast. Over time, those spikes in insulin production wear on the body, damaging cells and promoting excess storage of fat. So why would you ever eat white bread? "Even if you're cutting carbs, there's still a place for complex whole grains in your diet," says Mohr. "They leave you feeling fuller longer, and they provide the longest possible supply of sustained energy." Just watch out when you're buying something that claims to be whole grain. It may only look brown because it's colored with molasses. Rather than buying based on color, check the ingredient list. The only true whole-grain products are those that contain 100% whole wheat or whole grain listed as the first ingredient on the packaging.