Why some cancer patients may need to stick to a low-gas diet

Some cancer patients may need to be on a low-gas diet.
Eating a low-gas diet may help prevent unintended treatment side effects and keep discomfort at bay.

What you eat may have an impact on how well your cancer treatment works. If you have cancer in the abdominal or pelvic regions, for example, and are about to undergo a radiation therapy treatment, eating a meal with raw vegetables may cause gas and bloating, leading the radiation to be less targeted and affect more healthy tissue than it should.

Eating a so-called low-gas diet, though, may help prevent unintended treatment side effects and keep discomfort at bay.

In this article, we’ll explore:

If you’ve been diagnosed with cancer and are interested in a second opinion on your diagnosis and treatment plan, call us or chat online with a member of our team.

Radiation therapy and gas

Gas and bloating not only cause discomfort, they may also make treatments like radiation therapy less effective and contribute to unwanted side effects.

“Excessive gas can physically expand the intestines, which might inadvertently move the bowel into the radiation field,” says Kevin King, MD, Assistant Clinical Professor of Radiation Oncology at City of Hope® Cancer Center Downtown Chicago.

For patients with cancers that require radiation therapy to the pelvic and abdominal regions, reducing gas buildup and bloating may help doctors target radiation more accurately—ultimately protecting healthy tissues nearby. “This approach not only enhances the effectiveness of the treatment but also reduces potential discomfort and side effects for the patient,” Dr. King says.

Chemotherapy and gas

Chemotherapy’s association with gas and bloating is a little different from that caused by radiation therapy. Instead of being affected by gas and bloating, chemotherapy can cause the symptoms.

“Chemotherapy can cause intestinal bacteria to die, along with the cancer cells it’s targeting,” says Lora Reeves, MS, RD, LD, Clinical Oncology Dietitian, City of Hope Cancer Center Atlanta. “When changes in the microbiome occur, it can lead to gas, bloating and diarrhea.”

Chemotherapy may also slow down gastric motility—movement through the gastrointestinal (GI) tract—triggering gas and constipation.

What’s a low-gas diet?

In general, people react differently to different types of food. For example, eating spicy curry for lunch may cause one person to develop severe heartburn but not affect another person at all. Similarly, foods such as leafy vegetables and beans, are more likely to stimulate gas and bloating symptoms, but not in everyone.

Still, if a patient is going to undergo radiation therapy to a part of the body that could be affected by bloating, a dietitian may advise them to eliminate or reduce these gas-producing foods—many of which are high in fiber—from their diet.

“It’s hard because we really promote fiber and encourage our patients to eat foods that contain fiber—like whole grains and fruits and vegetables—but sometimes we have to pivot to advise our patients to hold back on these foods to reduce gas,” Reeves says.

What to eat on a low-gas diet

If your doctor or dietitian advises you to eat a low-gas diet, he or she will likely give you some ideas of what meals and snacks to include in your diet.

Here are some ideas of what to eat and what to avoid:

OK Avoid
Drinks Non-carbonated drinks, like coffee, tea, milk Beer, carbonated drinks, fruit drinks, sports and energy drinks
Fruits Berries, cherries, grapes, honeydew, lemons, limes, oranges, pineapple Apples, avocados, bananas, cantaloupe, mangoes, peaches, pears, plums, prunes
Vegetables and legumes Beets, carrots, corn, green beans, lettuce, peas, potatoes, spinach, tomatoes, white potatoes, zucchini Asparagus, artichokes, beans, broccoli, Brussels sprouts, cabbage, cauliflower, celery, collard greens, corn, cucumbers, kale, lentils, onions, peas, peppers, radishes, sweet potatoes, turnips
Starches Bagels, biscuits, cornbread, cream of wheat, dry cereals, English muffins, instant oatmeal, pancakes, waffles, white or wheat breads, white or wheat pastas and rice, tortillas Bran cereals, brown rice, granola, popcorn, whole grain breads
Eggs, meats, fish and poultry Lean meats, pork, poultry or fish that's baked, broiled, roasted or grilled, egg whites Fried meats, high-fat lunch meats like bologna and salami, hot dogs, sausage, egg yolks

You should also avoid dairy products like milk, yogurt and ice cream.

Examples of low-gas diet meals


Select one or more from each group listed below.

Carbohydrates: Cream of wheat, oatmeal, pancakes, waffles, cold cereal, bagels, English muffins, toast

Proteins: Low-fat yogurt, cottage cheese, low-fat string cheese, peanut butter, skim or soy milk

Fruits: Bananas, oranges, grapes, canned fruits, applesauce

Lunch and dinner

Select one or more from each group listed below.

Carbohydrates: White pasta, rice, bread/rolls, flour tortillas, potatoes (no skin)

Proteins: Baked/broiled meats, poultry and fish, nut butters, nitrate-free deli meats, cottage cheese, low-fat yogurt, low-fat cheese slice, skim milk, soy milk or rice milk

Fruits: Same as breakfast

Vegetables: Most cooked vegetables

Sources: Academy of Nutrition and Dietetics, National Institute of Diabetes and Digestive and Kidney Diseases

Other ways to reduce gas

Eliminating or reducing foods from your diet isn’t the only way to avoid gas and bloating. Simple behavioral changes may also help.

For instance, drinking through a straw, chewing gum and talking while eating can all promote gas production. Avoiding these behaviors before starting treatment may help reduce gas and bloating symptoms. Physical activity and making sure you stay hydrated by drinking plenty of water may also help with digestion.

You may be tempted to try Gas-X®, beano® or another over-the-counter gas relief product, but talk to your doctor first.

“You should always talk to your care team before adding any supplements,” Reeves says. “You don’t have to fly blind. You can get help.”

If you’ve been diagnosed with cancer and are interested in a second opinion on your diagnosis and treatment plan, call us or chat online with a member of our team.