A Taxonomy of Tummy Bloating: Your Symptoms Explained

Among the many matters of dietary and digestive distress, my patients most commonly complain of gas and bloating. Given how often I encounter this problem, one would think I'd have developed a magical dietary prescription to fix it, fast. But alas, I have not.

Here's why: Bloating is in the eye of the beholder. To some, it means excessive belching. To others, it means passing gas excessively. Some people define bloating as feeling like their stomach is distended; this type of bloating may or may not be accompanied by constipation. And then there are those to whom bloating is an appearance thing--the tummy that wakes up flat but looks "pregnant" later in the day, or the belly protrusion that persists despite weight loss.

To complicate matters, not all of these perceptions correspond to a clinical diagnosis of bloating, which is more narrowly defined as the presence of gas trapped in the abdomen or actual abdominal distension as observed by a doctor on physical examination. And even in the case of bona fide distention, not all bloating has a dietary cause at its root; several medical conditions can bring about these same symptoms. As a result, some detective work is required to truly understand the nature of an individual's bloated belly and to narrow down what dietary factors, if any, may be involved. Here are some common possibilities:

1. A carbohydrate trigger. With regard to this type of bloating, the common refrain is that people feel fine after breakfast, but the bloating starts up soon after. Within an hour of lunch, the stomach distends to the point where pants need to be unbuttoned, and it remains this way for the rest of the day. It is often only relieved upon waking up the next morning. Sometimes, veterans of low-carb dieting will say that that their bloating problem improved on a low-carb diet. In these cases, I'm often on the lookout for poorly-digested carbs--what we've referred to here as FODMAPs--as the culprit. Figuring out if symptoms seem to arise from ingesting certain types of sugar (lactose or fructose), sugar alcohols, dietary fibers, or so-called resistant starches (like those found in beans) can help patients avoid food triggers.

2. Constipation. Whether someone complains of a rock-solid belly or abdominal pain that builds as the day progresses, I ask if their symptoms are relieved when they poop. If so, we're probably looking at constipation as our fall guy. The reason? Normal intestinal gas gets trapped behind slow-moving poop and builds up as a result. The trick to eliminating (pardon the pun) this belly bloat is a very gradual increase in dietary fiber. Too much additional fiber too quickly can actually make the bloating worse, so the key is to ramp up slowly. Focus on insoluble fiber from bran, seeds, and fruit and vegetable skins rather than soluble fiber, like inulin, from processed, high-fiber cereals and snack foods. The former is much more likely to speed up the intestinal transit of poop while limiting the amount of gas produced as a byproduct.

3. Undiagnosed Celiac Disease. When patients tell me they look seven to nine months pregnant soon after eating a specific food, I often suspect Celiac disease or an intolerance to wheat or gluten. In these cases, I probe further to see if bread, pasta, flour, or beer seems a likely trigger. Often, a Celiac-related bloated belly can take some time to deflate--up to a day or two after eating the trigger food. Celiac-related bloating may also be accompanied by foul-smelling flatulence and diarrhea, though it's not unheard of to endure constipation instead. A simple blood test will tell your doctor whether further diagnostic testing is warranted.

4. Acid reflux or dyspepsia. Does you feel uncomfortably bloated in the upper belly region, particularly after eating? Are you uncomfortably full or nauseous after a normal meal? Do you burp excessively within an hour or so of eating? If you answered yes to any of these questions, your distress may be related to acid reflux or dyspepsia, aka indigestion.

I've found that this type of bloating is especially bad when someone eats a big, raw salad on an empty stomach; there's just something about dumping all that roughage on an acid-prone tummy that seems to churn up unpleasantries. With regard to (non-acid) dyspepsia, smaller, lower-fat meals are generally better tolerated, and a glass of seltzer may work wonders. In fact, despite the common belief that avoiding carbonated beverages will help prevent bloating, the opposite is generally true. Fizzy drinks can induce belching, which helps relieve the pressure from gas buildup in the stomach. Carbonated water has been proven to be more effective than tap water in easing symptoms of indigestion.

5. Excess tummy fat. If an otherwise thin person complains of bloating but denies constipation, discomfort, or excess flatulence, he or she may be carrying extra tummy fat. There are several reasons this can happen. Cigarette smoking can influence where fat is deposited, and it tends to favor the tummy. Chronic alcohol intake also favors fat deposition in the abdominal area--more so in men, but to a lesser degree in women, too. This has to do with an increase in the enzyme system designed to metabolize substantial alcohol intake; these enzymes are concentrated in the abdominal area and convert alcohol into storage-ready fats known as triglycerides. While beer has a reputation of being more likely to produce this type of effect--hence the term, "beer gut"--excess intake of any alcohol is equally likely to induce this phenomenon.

In some cases, natural body type can be a factor. Among women, so-called "apple shapes" are much more likely than "pear shapes" to retain fat in the midsection. This is, unfortunately, Mother Nature's mysterious plan for you. The best way to address this is overall weight loss from whatever diet plan works best for you. Eventually, some fat will come off the midsection--even among the apples. So-called "belly fat" diets do not disproportionally target abdominal fat, and no matter what popular TV doctors claim, dietary supplements don't do so either.

If belly bloat plagues you, consider whether any of the descriptions above fit your brand of bloating. Then, keep a written journal for one to two weeks that details foods eaten, symptoms experienced, and bowel movements passed (including times of day for everything noted). Include it all, no matter how inconsequential it may seem! Note your vitamins, alcohol and water intake, salad dressings, and even the M&M you snagged while passing a co-worker's desk. This record will be an invaluable diagnostic resource to your doctor or dietitian to help you pinpoint the exact cause of your bloating woes.

Hungry for more? Write to eatandrun@usnews.com with your questions, concerns, and feedback.

Tamara Duker Freuman, MS, RD, CDN, is a NYC-based registered dietitian whose clinical practice specializes in digestive disorders, Celiac Disease, and food intolerances. Her personal blog, www.tamaraduker.com, focuses on healthy eating and gluten-free living.