Earlier this year I was feeling as inflated as a Macy's Thanksgiving Day Parade balloon. I know, belly complaints are pretty common—research shows nearly 20 percent of women have chronic constipation and 14 percent have symptoms like pain or bloating—but this was happening so often I was getting cranky. Really cranky.

I was tempted to blame gluten—after all, I'd read the headlines about an Australian study that showed that eating the protein (found in wheat and other grains) can cause stomach ailments even in people who don't have celiac disease. And everyone knows someone who has cut gluten from her diet and looks and feels fantastic.

There was just one problem: Those headlines were wrong.

Over the last five years, gluten-free diets have gone from little-known concept to full-blown food craze, and recently those same scientists decided to run a more rigorous study to confirm that gluten—not something else—had been the troublemaker. (Props to responsible scientists.) They knew compounds called FODMAPs (for fermentable oligo-, di-, and monosaccharides and polyols) can also cause stomach issues. 

Gluten and FODMAPs are often in the same foods, so the researchers put 37 adults with tummy troubles on a diet free of both. After two weeks, everyone felt better! Then they started eating gluten again, and guess what? Only 8 percent of them had worse symptoms—so FODMAPs, not gluten, were likely what was bugging the other 92 percent. 

The takeaway? "There's some evidence gluten sensitivity exists, but probably only in a small number of people," said study author Jessica Biesiekierski, Ph.D., one of the world's top gluten investigators. "People who believe they have it are likely to benefit from eating fewer FODMAPs."

Belly 101
First, a primer: In your gut—the part of your body that digests food—there are trillions of bacteria that help your body break down what you eat, fight infections, even keep your mood steady. 

"They all have different functions, and the more diverse the community, the better your health," says Gerard Mullin, M.D., director of Integrative GI Nutrition Services at The Johns Hopkins University School of Medicine in Baltimore and author of The Gut Balance Revolution. But if any one type gets overgrown or depleted, your health may suffer. Of course, our modern lives can easily disrupt that perfect ecosystem: antibiotics, drinks with artificial sweeteners, binge drinking, and a bread-and-pasta-heavy diet can all throw things out of whack.

This is where FODMAPs come in. They're molecules found in five types of sugar: fructose (in foods like apples, pears, honey), lactose (in chocolate, milk, cottage cheese), fructans (in wheat, garlic, onion), galactans (in beans, lentils, soybeans), and polyols (in apricots, sweeteners). FODMAPs aren't unhealthy, per se, but they do have one thing in common: They're osmotic—that's fancy medical speak for something that pulls water into the small intestine during digestion, a process that can cause abdominal pain, bloating, and diarrhea. What's more, when bacteria in the large intestine break down these foods, they start to ferment, creating gas and adding to the discomfort. Most of us have no problem tolerating moderate amounts of FODMAPs, but small amounts can cause problems in people who are intolerant to them.

The solution, an increasing number of researchers say, is to temporarily nix FODMAPs. Studies show that following a low-FODMAP diet actually brings more relief to severe sufferers than interventions like medication, reducing symptoms like bloating and pain in 75 percent of cases. Dr. Mullin has also seen it spark weight loss in his patients—since rebalancing your gut bacteria may mean fewer cravings—but research hasn't documented this benefit yet.

Going Low-FO
Promises of a flat belly are tempting, but you should only try a low-FODMAP diet if you have chronic GI issues (like gas, bloating, cramping, and diarrhea) that your doctor has determined aren't caused by a more serious disorder, like celiac disease. (For occasional belly swell, doctors suggest cutting back on carbonated beverages and gum, and getting regular exercise.) If you do opt to go low-FO, here's how it works:

Eliminate all high-FODMAP foods from your diet for two to six weeks until symptoms subside. Since many high-FODMAP foods also have gluten, you will be eliminating most bread (*wipes tear*), but it's not a forever sentence. Once your symptoms clear up, reintroduce one food from one FODMAP group every three days. If symptoms return, you may have a food intolerance, like lactose intolerance; keep experimenting until you find how much of the trigger foods your body can happily handle, says Kate Scarlata, R.D.N., a Boston digestive-health dietitian and author of 21-Day Tummy Diet. And if you add back in all the foods you normally eat and no symptoms return, that may mean your gut bacteria just needed to be rebalanced, says Dr. Mullin.

Important note: You should ultimately reintroduce healthy high-FODMAP foods that aren't triggers, says Dr. Mullin. Many can lower your risk of obesity and even cancer. What's more, the indigestible fiber in foods like beans, whole grains, and fruit creates a latticework for good bacteria to glom onto and multiply, ensuring that your gut will stay well in the long run.

I followed the diet, and my gas and bloating disappeared after two weeks—that's all it took. Poof. Looking back, I shouldn't have been so surprised; over the past 18 months, I'd taken four courses of antibiotics (C-section, dental surgery, etc.); and with a new baby, I'd turned to quick, carb-heavy meals. After going low-FO, I lost two pounds and am comfortably wearing skinny jeans again. The best part: Feeling good has given me the pep to keep eating right. "When you're bloated, it's hard to feel motivated to embark on healthy eating because you feel fat even when you're not," says Scarlata. "What you eat really does affect you from head to toe."


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