It's been drilled into our heads that whole grains are heart-healthy and essential to a diet that keeps us slim and satisfied. But the wheat toast you opt for over a muffin or bagel in the a.m. may not be as smart of a dietary decision as once thought. In his new book Wheat Belly, preventative cardiologist William Davis, MD, argues that the world's most popular grain, found in everything from lager to licorice to lunch meat, is destructive to weight loss - and overall health.

According to Davis, the compounds found in wheat are responsible for appetite stimulation, exaggerated rises in blood sugar, and the release of endorphin-like chemicals that get the brain hooked on breads, pastas and crackers, while increased wheat consumption can also be linked to higher incidences of celiac disease, diabetes, heart disease, arthritis and schizophrenia.

If you think this talk about wheat sounds like a new spin on the gluten-free fad, it's not so simple. While wheat is the dominant source of gluten in the human diet - gluten is what gives dough the ability to be stretched, rolled and shaped into bagels, pretzels and pizza crusts and is the culprit underlying inflammatory damage to the intestinal tract in those with celiac disease - it also contains a unique carbohydrate called amylopectin-A, which sends blood sugar soaring higher than table sugar or a candy bar ever could.

This isn't your great grandmother's wheat - or waistline - we're talking about. Amounts of wheat's destructive compounds have increased over the past 50 years as the grain has been hybridized and crossbred to be resistant to drought and fungi, produce higher yields per acre, result in better baking consistency, and cost less to produce. Not surprisingly, the increase in wheat in the American diet parallels obesity rates that have nearly tripled since 1960.

We took a close look at Wheat Belly, chatted with Davis, and discovered eight ways that wheat could be wrecking havoc on your weight loss efforts and how going wheat-free can help you slim down.

Whole wheat is marketed as healthy

Studies performed during the 1980s show that when processed white flour foods are replaced with whole grain flour products, there is a reduction in colon cancer, heart disease and diabetes. While the science here can't be disputed, the logic is faulty, says Davis: "If something bad for you (white flour) is replaced by something less bad (wheat flour), and there is an apparent improvement, then plenty of the less bad thing is (considered) good for you. What was not asked: What about the effects of total removal? That's when far greater health benefits are witnessed." Davis compares this misguided nutritional advice surrounding whole grains to substituting hydrogenated fats for saturated fats, margarine for butter, and high-fructose corn syrup for table sugar.

Many of Davis's overweight patients report eating plenty of fruits, vegetables and whole grains and avoiding junk food, fast food, and sugary soft drinks, some adhering strictly to dietary guidelines and many exercising for an hour every day. Still, they continue to gain weight.

Until they cut out wheat, that is. Davis says he's witnessed the wheat belly weight loss effect thousands of times, watching patients replace processed, wheat-based foods with vegetables, nuts, meat, eggs, avocados, olives and cheese, and drop 50 to 100 pounds in one year. Among 30 patients he recently placed on wheat-free diets, the average weight loss was 27 pounds over the course of 6 months.

Whether patients on wheat-free diets consume non-wheat carbohydrates, like quinoa and millet as well as non-grain carbs such as fruit depends on the individual's carbohydrate tolerance, says Davis.

"For an established diabetic looking to become a non-diabetic, for instance, I would advise complete avoidance of these blood sugar-increasing foods since diabetes, by definition, is a disease of high blood sugars," he says. "On the other hand, a young, slender, athletic female usually can include these carbohydrate sources and do just fine." Still, most people fall somewhere in between, doing well with portion sizes of non-wheat carbohydrates of a half-cup or less, says Davis.

Bread breeds belly fat

Where there's glucose, there's always insulin, the hormone that allows entry of glucose into the cells of the body, where it's converted to fat. It works like this: When you eat wheat, your body gets a huge helping of a blood sugar-spiking carbohydrate called amylopectin-A. To move the sugars from the wheat into your cells where they can be used for energy - or stored as fat, the pancreas responds by releasing insulin. The higher your blood sugar is after eating, the more insulin that is released - and the more fat that is deposited in the abdominal area. When belly fat builds up, it floods the body with inflammatory signals that cause energy-requiring tissues, like muscle, to stop responding to a proportional amount of insulin. As a result, your pancreas churns out more and more insulin to help metabolize the carbohydrates you eat. Years of running your body through this high-blood sugar, high-insulin cycle result in the growth of visceral fat, or what Davis has deemed a wheat belly.

Carbs create cravings

If you've ever noticed that eating a grain-heavy breakfast at 7 a.m. leaves you scrounging for a snack by the time you reach your desk, you've experienced the effects of amylopectin-A. The surge in glucose and insulin and subsequent drop in blood sugar that follow wheat consumption set you up to be hungry approximately every 2 hours, regardless of whether or not your body really needs to eat, says Davis.

Davis suggests snacking on hearty portions of very low or no-carb foods, even those that are high in fat or calorically dense such as nuts and cheeses.

Wheat eaters eat more

Thanks to an appetite-revving wheat component called gliadin - and that all-day cycle of cravings for wheat and non-wheat-containing foods alike - it's no surprise that, on average, those who consume wheat eat more overall. According to Davis, wheat eaters generally consume an extra 400 calories per day. Over the course of a year, the equivalent of 42 pounds of weight gain.

"On the other hand, (people who follow wheat-free diets) naturally consume 350 to 400 fewer calories per day because they aren't craving food every 1.5 to 2 hours," says Davis, adding that by picking wheat-free foods you'll also reduce your exposure to sucrose, high-fructose corn syrup, artificial food colorings and flavorings, cornstarch and so on.

Wheat messes with estrogen

Grow yourself a wheat belly and you won't just need a bigger belt; you may also need a man bra. In males, visceral fat spurs the production of estrogen, which results in the growth of breast tissue and leads to what scientists call gynecomastia, or what your friends probably call "man boobs."

For women, a surplus of estrogen caused by excess belly fat raises the risk for breast cancer. In a Journal of the National Cancer Institute analysis of nine breast cancer studies that included a total of more than 2,400 women, breast cancer risk in postmenopausal women with excess visceral fat was double that of slender premenopausal women who did not have excess belly fat. Other studies suggest that excess belly fat can increase a women's risk for breast cancer as much as four-fold.

Your brain becomes addicted

When you grab a coffee or pour a glass or two of wine, you're looking for a certain fix. But when you eat wheat, you consume it for its nutritional value - or so you think.

What makes wheat the real bad guy is its addictive property, which it doesn't share with other grains, like millet and flax, says Davis. Wheat stimulates your appetite so you want more and more of it and when you stop eating it, your body goes through withdrawal symptoms. In fact, wheat's effect on the brain is the shared with that of opiate drugs.

Researchers at the National Institutes of Health found that polypeptides in gluten have the ability to penetrate blood-brain barriers. Once they gain entry into the brain, wheat compounds bind to the brain's morphine receptors, the same receptors to which opiate drugs bind, producing a sense of reward or mild euphoria.

Eating wheat zaps energy

"When you take wheat out of the diet, you see incredible turnaround in health far more than you'd ever predict," says Davis. "When someone gives up wheat, there's a very frequent and marked increase in energy and sleep quality," he says. While there's not a lot of research on the topic, Davis speculates that the connection can be explained by the absence of sharp swings in blood sugar and resulting energy slumps.

Swapping processed, wheat-based foods for veggies, fruit, nuts and dairy may also be precursors to better sleep, more energy and more stable moods.

"Gluten-free" foods are not the answer

Even if you don't have a wheat allergy, perhaps you've picked up gluten-free cookies, pasta or cereal because they just sound healthier. Truth is, many gluten-free foods are made by replacing wheat flour with corn starch, rice starch, potato starch, or tapioca starch, which hike up blood sugar even more than the amylopectin-A in wheat. This is especially hazardous to weight loss, since gluten-free foods, although they don't trigger a neurological response like gluten does or stimulate your appetite like gliadin does, still trigger the glucose-insulin response that packs on pounds.

Davis suggests removing wheat from your diet and enjoying larger portions of other healthy foods, like baked chicken, green beans, scrambled eggs or salad. If you're worried about not getting enough fiber, increase your consumption of vegetables and raw nuts and fiber intake will actually go up, says Davis. In fact, two slices of whole grain bread containing 138 calories contains about the same amount of fiber as 138 calories of nuts (about 24 almonds).

If you're itching to try a wheat-free diet, try a gradual withdrawal from grains, suggests Davis. First, eliminate wheat from your dinner for 1 to 2 weeks, then get rid of it at lunch for a week or two. Finally, try going wheat-free at breakfast, when it's often hardest to let go of cereal and other grain-based breakfast foods.

"Or go 'cold noodle,' advises Davis. "You'll be confronted with pain upfront, but you'll emerge feeling much better."