High-Protein Diets and IBS Are Not a Great Mix

There's no question high-protein, low-carb diets like the Atkins or South Beach Diet are popular these days. And you may have heard that some carbs are bad for irritable bowel syndrome (IBS). But do these programs — or any high protein approach — fit into an irritable bowel syndrome diet plan?

Dietitian experts say a high-protein diet is not good for IBS because it can reduce the amount of fiber you're getting and increase the fat in your diet, leading to constipation.

IBS is a chronic condition that causes pain, gas, cramps, nausea, diarrhea and constipation. Certain carbohydrate foods can trigger symptoms, particularly those containing fermentable carbohydrates called FODMAPs, Johns Hopkins Medicine says. These are present in several carb-forward foods such as:

• Milk products.
• Wheat.
• Beans and legumes.
• Some fruits (such as apples, cherries, pears, peaches and more).
• Some vegetables (such as broccoli, cabbage, asparagus, onions and garlic and more).

With IBS, you might be advised to follow a low-FODMAP diet temporarily — and it might lead you to believe that a protein-heavy diet that eliminates carbs is the answer to IBS symptoms.

​Read more:​ How the Low-FODMAP Diet for IBS Works, and How to Get Started

With high-protein diets, you're typically lowering your intake of carbs. But, avoiding troublesome carbs doesn't mean eliminating all carbs, according to Beth Rosen, RD, CDN, dietitian and owner of Goodness Gracious Living Nutrition in Southbury, Connecticut. "Our guts need carbohydrates," she says, noting that our brains run on glucose, a sugar. "If we're not getting it, our bodies cannibalize our muscles."

Many sources of carbohydrates — fruits, vegetables and whole grains — also contain the fiber our bodies need to feed the friendly bacteria in our digestive system and to help keep stool moving through the large intestine, says Cari Riker, RDN, LDN, registered dietitian nutritionist and owner of Riker Nutrition Consulting in Brentwood, Tennessee. Cutting out carbs may also lead to cutting fiber.

"People on a high-protein diet might experience constipation," she says. In addition, eating too much meat can mean more fat in the intestines, which worsens constipation, Riker cautions. "Motility issues can slow things down," she says.

Both dietitians say they prefer a balanced approach to nutrition, with meals that include lean protein, plus whole grains, fruits and vegetables that are low-FODMAP. "A well-rounded diet works best for IBS," Rosen says. "Make sure you're choosing lean sources of protein," Riker adds. And, "You need to add low-FODMAP carbohydrates."

Riker recommends these sources of protein:

• Lean, non-red meats, such as chicken and fish.
• Silky or soft tofu, not firm or hardened tofu.
• Canned, drained and rinsed chickpeas (garbanzo beans) and lentils, not dried and soaked versions.
• Quinoa.
• Protein powder made from egg whites (albumen) or brown rice. (Whole eggs are OK, too.)
• Lactose-free milk and almond milk.

Rosen adds these:

• Nuts, excluding pistachios and cashews.
• Hard or aged cheeses, including cheddar, brie, camembert, mozzarella and parmesan. (Avoid fresh cheeses, such as cottage cheese and ricotta.)

According to the University of Wisconsin School of Medicine and Public Health (UW Health), these carb-containing foods are low-FODMAP:

• Vegetables: Lettuce, spinach, green beans, potatoes, radishes, eggplant, carrots, tomatoes, zucchini and cucumbers.
• Grains: Sourdough bread, gluten-free bread or cereal, oats, rice, millet, amaranth, quinoa, tapioca, cornmeal, corn chips and corn tortillas.
• Fruits: Bananas, oranges, grapes, honeydew melons, strawberries, papayas, raspberries, kiwis and pineapple.

These choices can help you maintain a balance of healthy gut foods, preferred by Riker and Rosen.

IBS symptoms and trigger foods vary from person to person. This is why once the condition has been diagnosed, patients are typically placed on an elimination diet for several weeks, then have foods reintroduced to see which are problematic and which can be enjoyed, Johns Hopkins Medicine says.

Portion size is important, too, UW Health says. The larger the serving of a problem food, the worse symptoms will be. Many people with IBS can consume small amounts of FODMAP foods without ill effects.

Lifestyle changes can also help keep IBS under control. According to Kaiser Permanente, drinking plenty of water and getting adequate exercise also aids digestion. Riker recommends patients get the sleep and rest they need and learn how to better manage stress, as stress can worsen symptoms.

​Read more:​ Your Ultimate Guide to Living Well With IBS