What you should know before starting the low FODMAP diet that can help treat GI issues like bloating and diarrhea
- The low FODMAP diet is a temporary, elimination diet designed to help people with gastrointestinal disorders.
- On a low FODMAP diet, you should avoid foods that contain large amounts of FODMAP carbs like fructose, sorbitol, and lactose.
- After you've cut these foods out for four to six weeks, you can slowly add them back in one at a time to find out which foods bother your stomach.
- Visit Insider's Health Reference library for more advice.
People with gastrointestinal (GI) disorders like irritable bowel syndrome (IBS) often have trouble digesting certain kinds of carbohydrates, which causes a lot of uncomfortable symptoms like bloating, gas, abdominal pain, diarrhea, and constipation.
In the early 2000s, researchers began looking for ways to describe these carbohydrates: Enter FODMAPs, short for fermentable, oligosaccharides, disaccharides, and monosaccharides, and polyols.
FODMAPs refer to the carbohydrate compounds that can cause IBS-like symptoms and include sugars like fructose, lactose, and sugar alcohol sorbitol. Here's who should try a low FODMAP diet and how to follow it.
Who should try the low FODMAP diet?
The low FODMAP diet isn't designed for everyone. It's a type of elimination diet specifically catered to help people with GI discomfort like bloating, diarrhea, constipation, and stomach cramps.
"A low FODMAP diet is really only something that needs to be tried if someone has gastrointestinal symptoms," says Jesse Houghton, MD, senior medical director of gastroenterology at SOMC Gastroenterology Associates. "Or if someone has IBS, celiac, food allergies. If a person is not experiencing any frequent bloating, flatulence, diarrhea or discomfort, a low FODMAP diet is not necessary.
On the low FODMAP diet, people begin by eliminating foods containing high levels of FODMAPs — called high FODMAP foods — from their diet for four to six weeks.
After that, they start slowly reintroducing foods back into their diet one at a time. That way, they can identify which foods trigger their GI symptoms so that they can avoid those foods in the future.
How do I start a low-FODMAP diet?
To start a low-FODMAP diet:
- Check with your doctor to see if a low-FODMAP diet will work for your individual needs.
- Prep your fridge and pantry by taking out or storing away foods you'll want to eliminate for four to six weeks.
- After four to six weeks, re-introduce a single food — that you had eliminated — every three days.
- As you're reintroducing food, keep a journal of which foods you introduced, when you introduced them, and if they caused any GI symptoms.
- Discuss the results with your doctor to develop a long-term meal plan that works for you.
What foods should I eliminate on a low FODMAP diet?
When starting a low FODMAP diet, you have to carefully examine food labels. Depending on your body and your specific issues, you may be looking for ingredients like fructose, sorbitol, and lactose.
Below are the main FODMAP carbs to avoid:
Fructose: Foods high in fructose include many processed foods that contain high-fructose corn syrup including sodas and candies. But you can also find relatively high amounts of fructose in certain fruits like apples, watermelon, dried fruits, and more.
Sorbitol: Sorbitol is often added to foods as a sugar substitute and will show up on nutrition labels as an E420 additive. Some foods that contain sorbitol include certain diet drinks, sugar-free chewing gums, and beers. It's also found naturally in many fruits including pears, plums, cherries, apples, nectarines, apricots, and more.
Lactose: Lactose is a sugar that you can find in most dairy products including milk, cheese (though older, harder cheeses contain little lactose), yogurt, and ice cream. However, it can also turn up in unexpected places including bread, donuts, cookies, processed meats, salad dressings, and more. Check the nutrition label to be sure.
Mannitol: Mannitol occurs naturally in pumpkin, seaweed, celery and mushrooms. But many liquid medications like liquid gel capsules and cough medicines can also contain it.
Fructooligosaccharides: These starches turn up in asparagus, tomatoes, wheat, and onions, to name a few. They're also added as a low-cal sweetener to certain cereal bars, candies, and yogurts.
Xylitol: Like mannitol and sorbitol, xylitol can show up in certain liquid medications and chewing gum. It also occurs naturally in strawberries, plums, raspberries, and cauliflower.
Galactooligosaccharides: Beans, lentils and other legumes can contain high levels of galactooligosaccharides.
Maltitol: This reduced-calorie sweetener shows up in lots of "diet" foods and is often used as the sweetener in sugarless candy, chocolate, and baked goods.
What foods should you eat on a low FODMAP diet?
With all of these restrictions, it's hard to figure out what you should eat.
For examples of low and high FODMAP foods, check out this list from the University of Virginia Health System. Based from the available foods in that list, here's what a day eating low FODMAP foods may look like, depending on your dietary restrictions:
- Breakfast: One medium banana and some scrambled eggs. Pair it with an espresso or cup of green tea.
- Snack: A glass of nut milk.
- Lunch: Kale and sweet potato salad with pecans. Dress it with a mix of olive oil, salt, and vinegar.
- Snack: Fruit-vegetable smoothies made from low FODMAP fruits and veggies.
- Dinner: One chicken breast with a side of rice and green beans.
Don't try the low FODMAP diet alone
Don't try the low FODMAP diet without checking in with your healthcare provider first. "The diet should be done under supervision of an MD or RD, and the time frame depends on the GI symptoms," says Kim Pierce, a registered dietitian and founder of The Outdoors Dietitian, LLC.
That's because eliminating high FODMAP foods from your diet comes with some risk. Turns out, your body needs these fermentable carbs to feed the good bacteria in your gut. Eliminating all FODMAP-containing foods could starve those bacteria, explains Shawn Talbott, a nutrition and biochemistry expert.
"When those bacteria are at suboptimal levels, we see increases in inflammation, stress, depression and other problems," Talbott says.
That's why it's important to slowly add high FODMAP foods back into your diet. Once you identify the foods that don't trigger any GI symptoms, you can eat them without worry.
The low FODMAP diet "is a short-term elimination diet," says Pierce. "This is not a sustainable long-term diet."
If, however, you find that you need to eliminate the bulk of high FODMAP foods, you should consult a registered dietitian about any key nutrients you might be missing and how to balance your diet so you're still getting enough nutrients.
Insider's takeaway
If you have issues with your gastrointestinal tract or have a chronic condition, the low FODMAP diet might help you figure out which foods trigger symptoms of GI discomfort.
The low FODMAP diet is an elimination diet that helps you isolate which sugar compounds found in carbs might irritate your GI tract. The diet lasts four about four to six weeks before you begin slowly adding back in certain food groups one by one to find out which ones you may want to cut from your diet long-term.
Consult your physician before starting this diet to make sure it'll work for your personal health needs.
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