Anyone who has ever tried the low-carb route can tell you how important fiber is to your diet. Without it, all of that protein just sits in your gut and turns into a lead sludge that can make any trip to the ladies' room require two magazines and maybe a book for backup. When your ass falls asleep on the toilet, it's a sign that maybe you need more vegetation in the diet. Prunes are an option too, but, well, sorry, just because we can't poop, that doesn't mean that we have to eat grandma-fare.

Okay, so we went for the heart of the matter, but that's just because when you're under the gun, it becomes a very pressing issue. Even if you're not the c-word (constipated), it doesn't mean that you're necessarily getting enough fiber in your diet.

No matter what nutritional program you're following, fiber is the superhero of the eating arena. You eat less because you're more full, plus all that food stays with you. To experiment, try having a bowl of steel-cut oatmeal for breakfast one day and then a McDonald's breakfast burrito the next. We're willing to bet that you'll be chewing on your cubicle wall by your 10 o'clock meeting (or stealing from the receptionist's jelly bean dish) on the burrito day, while the oatmeal will allow you to coast into a healthy late lunch. One of our friend's favorite tricks with her kids is to tell them that they can have a piece of cake as an afternoon snack, but they have to eat an apple first for the vitamins. Half of the time, the kid opts to save the cake for after dinner. And just try to crave chocolate after polishing off a bowl of Kashi Good Friends. That stuff will kick your hunger's ass.

Even low-carb diets can fit some greens into the program, and Stonyfield Farms Banilla yogurt packs a whopping 16 percent of your daily requirement of fiber into a single serving. How are they doing that? The yogurt tastes like pudding! Where are they hiding the fiber? For 4 grams of fiber, would you rather have delicious organic yogurt, or the driest, nastiest whole grain bread on the shelves that will make a sandwich requiring two glasses of milk to get through, and afterward makes the top of your mouth feel like it's been attacked with a cheese grater. No brainer. Top your treat with some granola bits (more fiber!) and you'll swear that you're eating your dessert for breakfast.

Surprisingly, whole grain crackers like Wheat Thins are just fooling you with their healthy image, while celery sticks, carrots, popcorn and broccoli all pack a huge punch in the fiber department. There are also products on the market that allow you to add more fiber to your dinner, so you can turn up the volume of unsuspecting fare like soups, cakes, meatloaf or even a glass of milk. How sneaky! Almost like we're involved  with nutritional espionage.

Who knew fiber could be such a sexy bitch?