Never eat these foods if you want a flat stomach

If your typically flat stomach has been looking and feeling extended, there can be more than one cause. According to research published in 2005 in the journal Gastroenterology, four factors are involved in bloating: "a subjective sensation of abdominal bloating, objective abdominal distention, volume of intra-abdominal contents, and muscular activity of the abdominal wall." Bloating can be extremely uncomfortable, but it's also incredibly common. A 2008 paper published in the journal Gut found that 19 percent of individuals studied experienced bloating and 8.9 percent experienced visible abdominal distention.

The problem is that many (though certainly not all) of the foods that can keep you from achieving a flat stomach are still very nutritious. Cutting them out completely may mean missing out on important micronutrients and healthy sources of energy. You may decide to simply reduce the amount of these foods that you eat or find a good-for-you alternative that's easier on your waistline. And remember, a flat tummy isn't the be-all and end-all. Good health and a positive relationship with both food and your body is important. Nevertheless, these are some of the foods that cause distention.

Beans

Beans, beans, the magical fruit. The more you eat, the more you ... bloat? Beans contain carbohydrates known as FODMAPs (fermentable oligo-, di-, mono-saccharides and polyols). Kristen Carli, registered dietitian, told Health Digest, "For many people with irritable bowel syndrome (IBS), forms of short-chain carbohydrates called FODMAPs can produce GI symptoms, including bloating." She explained that among sensitive individuals, FODMAPs are not properly digested in the small intestine and instead travel to the large intestine, where they are consumed by gut bacteria. As the bacteria feed, they produce gas, which leads to bloating. There are a number of FODMAPs, but galacato-oligosaccharides (GOS) are the group most prevalent in beans. Unfortunately, GOS equals gas.

If you regularly experience stomach-stretching bloat after eating beans or other FODMAP-containing foods, Carli suggests trying a low-FODMAP diet under the guidance of a medical professional. She explained, "The low-FODMAP diet is an elimination diet, where foods containing the FODMAPs are avoided for at least four weeks, then slowly and individually re-introduced. The purpose of the low-FODMAP diet is to identify which foods are the patient's individual triggers."

Lentils

Like beans, lentils are a legume and high in FODMAPs. But, also just like beans, they are packed with nutrition, so giving them up entirely might not be the best move for your health. For example, one cup of lentils provides 17.9 grams of protein, 15.6 grams of fiber, 90 percent of your daily folate needs, 37 percent of your iron requirement, and 49 percent of the manganese you need daily.

So what options do you have if you love lentils but lentils don't love you? You may be able to get away with simply cutting back on the amount of legumes you eat. The Grains & Legumes Nutrition Council suggested that sensitive individuals limit legume serving size to a quarter cup. Beano (or a similar medication) is another possibility. This over-the-counter product contains alpha-galactosidase, an enzyme needed to digest the galacato-oligosaccharides (GOS) in lentils and other legumes.

Research published in the Journal of Family Practice concluded that Beano does, in fact, prevent the gas, bloating, and other GI symptoms associated with eating legumes. How you prep your lentils also makes a difference. Monash University noted that FODMAPs leach into cooking water, so draining legumes after cooking them may make them less bloat-inducing.

Onions

Inulin and oligofructose are two types of fructan, a carbohydrate found in a number of plant foods. Americans eat a lot of fructans, and according to a paper published in the Journal of Nutrition, approximately 25 percent come from onions alone. The bad news for onion-lovers is that fructan is a FODMAP and therefore may cause bloating in susceptible individuals.

Some people also have an onion sensitivity. As a 2013 study published in the journal African Health Sciences explained, these individuals produce antibodies against onions and, often, other vegetables in the allum family such as garlic. For these individuals, eating onions triggers an immune response. This may exacerbate uncomfortable symptoms such as bloating.

If onions don't sit well with you and you want to keep your stomach looking and feeling flat, there are many options for creating flavorful dishes without them. Tasty alternative aromatics include celery, carrots, and bell peppers, and spices such as pepper and cumin can liven up many dishes.

Wheat

A paper published in the Journal of Nutrition found that a whopping 70 percent of fructans in the American diet comes from wheat. In fact, a 2018 study published in the journal Gastroenterology concluded that fructan (a FODMAP sugar) may actually be the trigger for people who believe they have a non-celiac gluten sensitivity. Whether fructan or gluten is the cause, bloating is often the result. A 2014 study found that approximately 87 percent of people with non-celiac gluten sensitivity experienced bloating after eating wheat (via Healthline).

Bloating is also a common complaint among individuals with celiac disease. According to the Mayo Clinic, celiac disease is an autoimmune condition in which eating gluten causes the immune system to attack the small intestine. Over time, this damage can put individuals at greater risk for nutritional deficiencies, brittle bones, infertility, and cancer.

Luckily, there are a number of grains that are both gluten-free and low in FODMAPs. These include brown rice, buckwheat, millet, oats, and quinoa.

Asparagus

Besides making your pee smell funny, asparagus can also lead to a round, bloated belly. That's because it's packed with a variety of FODMAP carbohydrates. In fact, asparagus contains fructose, fructan, and mannitol, according to Healthline. Other high-FODMAP veggies include artichokes, beets, Brussels sprouts, cauliflower, and mushrooms. If you need something lower in FODMAPs, bell peppers, leafy greens like kale and spinach, green beans, and zucchini are all good choices.

Of course, just because asparagus and some other vegetables are high in FODMAPs, that doesn't necessarily mean they're unhealthy. As such, not everyone should look to cut them out of their diets as that would mean missing out on all the important micronutrients they contain. 

According to Monash University, the way veggies are preserved or prepared may influence FODMAP content. Cooking may reduce FODMAP levels, but it's unclear by how much. Pickling, however, seems to cause a much greater reduction.

Probiotics

Having a diverse, healthy gut microbiome is important to good health. These friendly bacteria, which live mostly in our large intestine, perform a number of important functions, including assisting with digestion and supporting the immune system. It's no wonder then that many people have turned to probiotics in an effort to boost their health.

Probiotics contain billions of live, active beneficial bacteria, and the hope is that on the way through your digestive tract they'll take up residence and become part of your personal ecosystem. Probiotic foods and supplements contain a variety of bacteria strains, but most are from the groups Lactobacillus and Bifidobacterium. But, ironically, probiotics can actually increase GI upset, including bloating, in some people.

According to a 2010 study published in the American Journal of Health-System Pharmacy, while probiotics are generally well-tolerated, bloating and gas are the most often reported side effects. If a probiotic is causing unwanted bloat, you may want to try a different type (such as swapping supplements for sauerkraut) or dial back the dosage. Or you may want to simply stick it out for a little while; Healthline noted that these symptoms are temporary.

Milk

Milk and many other dairy products can cause bloating and a number of other unpleasant GI symptoms in the majority of the world's population. A 2013 paper published in the European Review of Medical and Pharmacological Sciences noted that approximately 75 percent of the global population loses the ability to digest the sugar lactose, found in milk and other dairy products, at some point in their lives.

Lactose intolerance occurs when the small intestine can no longer produce enough of the enzyme lactase to break down the lactose in the dairy products we eat or drink. How much lactase a person can produce will dictate just how lactose intolerant they are. Undigested lactose moves to the large intestine, where it's consumed by our gut bacteria. As the bacteria eat the sugar, they produce gas, which leads to bloating — bye-bye flat stomach.

If you're lactose intolerant and want to avoid the bloating dairy products can cause, you can take Lactaid pills. These contain the lactase your body needs but can't produce enough of on its own. You can also stick to dairy products that are low in lactose because of how they're made. These include hard cheeses, butter, yogurt containing active cultures, heavy cream, and kefir.

Sugar-free gum

Even though sugar-free gum may never make it to your stomach, it can have a big impact on your midsection. As Alicia Romano, a registered dietitian at Tufts Medical Center, explained, "For one thing, we naturally swallow a lot of air while chewing gum — sugar-free or not. Extra air swallowed can mean extra gas."

Another culprit Romano identified is sugar alcohols. Sugar alcohols (which are neither sugar nor alcohol) are a group of compounds found naturally in some fruits and vegetables. These polyols can also be created synthetically and added to processed foods like gum as a low-calorie sweetener. They are the "P" in FODMAP and many people have difficulty digesting them, leading to bloating.

Registered dietitian Joy Dubost explained in an interview with U.S. News & World Report that the poor digestibility of sugar alcohols is the reason manufacturers like to use them — your body can't absorb many calories from them as they pass through your system, so they're an obvious ingredient choice for low-cal "diet" foods.

Your best bet to avoid bloating is to simply avoid gum altogether. But if you need something to chew on, you may want to try regular gum made with real sugar.

Pears

Most people consider fruit to be a healthy snack option, but certain fruits, including pears, can lead to bloating, especially when eaten in excess. Pears are high in fructose, a simple sugar found in sweet fruits and some vegetables. Fructose is a FODMAP, which means some people have problems absorbing it properly. A 2016 study published in Molecular and Cellular Pediatrics noted that difficulty absorbing fructose can lead to excess gas in the large intestine. Other fruits high in fructose include apples, bananas, watermelon, mango, and kiwi. Lower-fructose fruits include apricots, berries, citrus fruits, and cantaloupe.

Pears are also high in sorbitol. Sorbitol is a naturally occurring sugar alcohol present in some fruits that's also added to processed foods as a lower-calorie alternative to regular sugar. Like other sugar alcohols, sorbitol is difficult for some people to digest and can cause gas and bloating. Other fruits high in sorbitol include apples, cherries, apricots, nectarines, and plums. Fruits low in sorbitol include berries, citrus fruits, bananas, and kiwi.

So, if you're sensitive to both fructose and sorbitol and are wanting a flat stomach, your best fruit options are berries and citrus fruits.

Sparkling water

We hear it all the time: Hydrate, hydrate, hydrate! And while water is the best option, the type of water you choose can have a big impact on how your stomach looks and feels. Many people enjoy the fizz of sparkling waters like La Croix and Perrier, but the carbonation you love can lead to bloating.

According to an article published in Slate, sparkling water can either be carbonated naturally from mineral springs or artificially created through the introduction of carbon dioxide gas. Regardless of how they got there, though, the bubbles in your sparkling water will meet one of three fates once they reach your stomach. As Dr. Aja McCutchen explained in an interview with Eating Well magazine, the first possibility is that the carbon dioxide will be burped out. Alternatively, it may move into your small intestine, where it will be absorbed into your bloodstream. But sometimes the gas simply sits in your stomach, causing bloating.

If you find that sparkling water causes problems, you may want to stick to regular still water or drink your sparkling water more slowly to allow the carbon dioxide more time to work its way out of your stomach.

Booze

Alcohol can leave you feeling bloated and puffy after a night out drinking with friends. According to Healthline, alcohol is inflammatory, and this inflammation can cause swelling in the body, particularly the GI tract and the face. These effects can be exacerbated by the sugar and carbonation found in some types of alcohol and mixers.

Beer, for instance, can be especially bloat-inducing. Not only is it inflammatory, but it's also loaded with carbonation. The yeast that converts grain into alcohol produce carbon dioxide in the process, and many brewers add in additional carbonation during bottling. The colder a beer is kept, the more carbon dioxide can be dissolved in it, leading to a stronger fizzy bite when you drink it.

The key to minimizing alcohol-induced bloat is to simply drink less. According to the 2015–2020 Dietary Guidelines for Americans, men should limit themselves to two "standard" drinks daily, while women should stick to one. A standard drink is equivalent to 12 ounces of beer, 7 ounces of liquor, 5 ounces of wine, or 1.5 ounces of high-proof spirits. Healthline noted that drinking plenty of water before, during, and after consuming alcohol can also prevent bloating.

Canned soup

A can of soup is a quick and easy meal option and especially lovely on chilly days, but these soups are packed with sodium that can lead to water retention. According to the 2015–2020 Dietary Guidelines for Americans, sodium intake should be limited to 2,300 mg a day. The report noted, however, that the average American consumes approximately 3,400 mg daily, largely from processed foods, breads, deli meats, and canned soups. In fact, research conducted by the Centers for Disease Control and Prevention found that soup was the fifth leading source of sodium in the American diet, accounting for 4.3 percent of total intake.

All this sodium can lead to bloating. A 2019 study published in the American Journal of Gastroenterology found that a diet high in sodium increased risk of bloating by approximately 27 percent. To make matters worse, soup is mostly liquid, which means it takes up a lot of space in your stomach, which can lead to a bulging midsection.

A more waistline-flattering alternative is to make your own soups, which allows you to control the sodium content. Many are easy "set it and forget it" recipes, and large batches can be divided up and frozen for later.

Popcorn

When it comes to having a flat stomach, popcorn is double trouble. First of all, it's very easy to eat a lot of the stuff. As Healthline pointed out, "A serving of popped popcorn is roughly 4 to 5 cups popped, which is the amount you get from 2 tablespoons of unpopped kernels." Because it's so light and airy, many people overindulge and can eat a whole bag (2 to 3 servings, likely 10 to 15 cups of popcorn) during a movie. This large volume of food at a single sitting can temporarily leave your stomach looking anything but flat.

And if you enjoy your popcorn salted, the sodium may lead to water retention and abdominal puffiness. According to WebMD, movie theater popcorn is particularly problematic. The sodium levels in the popcorn tested ranged from 210 mg in a small container from AMC to a staggering 1,500 mg in a large tub from Cinemark. Combine salty popcorn with a sugary soft drink that doesn't offer much hydration and your body will be holding on to every drop of water it possibly can.

To keep your stomach looking flat, you may want to consider sticking with unsalted or lightly salted popcorn and measure out a single serving in a bowl instead of grazing from the bag.

Coffee

Your morning cup of joe could be setting you up for a day full of uncomfortable bloating. According to a paper published in the Scandinavian Journal of Gastroenterology, drinking coffee stimulates production of gastrin, the hormone responsible for triggering the release of stomach acid. Compounds in coffee also stimulate the muscles of your colon to move. The result? Coffee predisposes you to gas and bloating in two different ways.

As Healthline noted, excess stomach acid can cause bloating and abdominal discomfort (as well as a host of other unpleasant GI symptoms, such as heartburn, nausea, and diarrhea). At the other end of your GI tract, problems with the movement of the intestinal muscles can also cause bloating.

But giving up coffee may be easier said than done. According to HuffPost, 55 percent of coffee lovers would rather gain 10 pounds than give up coffee forever, while 52 percent would pick coffee over a shower in the morning if they were forced to choose. In fact, Americans drink about 146 billion cups of coffee each year. Still, if you want to keep your stomach looking flat, you may want to think about switching to decaf or tea.