5 Hardest Foods to Digest

Indigestion by any other name—gas, bellyache, heartburn, upset stomach, bloating—is still indigestion, or the inability to digest food properly. Whatever you call it, a digestive problem can be inconvenient at best, and often downright painful.

Digestive disorders can be caused by a variety of underlying medical conditions, such as gastro-esophageal reflux disease (GERD), when stomach acid flows backward, and up into the esophagus (the tube that connects the throat to the stomach); gastritis, when the stomach lining is inflamed; or irritable bowel, when food does not pass through the digestive tract at a normal rate. If indigestion is chronic, speak with a doctor or dietitian to assess the problem. You may have to avoid certain foods altogether when your condition flares up.

But indigestion can also be a temporary result of overeating, eating too quickly, eating under stress, or eating certain types of food, according to Eamonn M. M. Quigley, MD, section chief of gastroenterology at Houston Methodist Hospital. In that case, it may just be a matter of revamping your eating habits. In addition to eating slowly, watching your portion sizes, and checking your emotions, you may want be cautious about eating the following foods:

1. Red Meat

Humans more easily digest meat proteins than vegetable proteins, but meat often stays in the stomach longer, which can interfere with digestion in general by slowing down the digestion of other foods. Delays in digestion can result in gas formation and bloating. Since fat slows down digestion, fatty meats can be harder to digest than leaner cuts. Cooking methods that toughen meat, such as pan-frying and dry roasting, or overcooking by any method can also make meat harder to digest.

What to Do: Grinding or cutting up meat into small pieces before eating helps ease digestion.

2. Legumes (Beans, Lentils and Split Peas)

Black beans, kidney beans, pinto beans, lentils and the like are high-fiber carbohydrates. Carbs are not digested in the stomach; they are digested by enzymes found in the small intestine. But the fiber component of carbohydrates, which can take a while to get from the stomach to the intestinal tract, contains an indigestible sugar called raffinose, which cannot be broken down until it reaches the colon, toward the end of the digestive tract.

Once in the colon, bacteria ferment and break down raffinose, a process that is accompanied by gas and bloating. Their notorious gaseous reputation aside, beans are high in protein and their fiber is ultimately valuable to digestive health.

What to Do: Eat small amounts of beans on a regular basis until your gastrointestinal tract adjusts.

3. Cruciferous Vegetables

Like legumes, cruciferous vegetables such as broccoli, Brussels sprouts, cabbage, and cauliflower also contain the indigestible sugar raffinose, which can ultimately cause gas buildup in the colon that leads to uncomfortable bloating. The degree to which you produce gas depends on the bacterial makeup of your gastrointestinal tract.

What to Do: Adding prebiotic and probiotic foods to your daily diet will help lower the number of gas-forming bacteria in your gut and maintain digestive system health. Prebiotic and Probiotic foods include yogurt, kefir or buttermilk with live cultures, kimchi, miso, fresh sauerkraut and other fermented foods.

4. Coffee and Other Caffeinated Foods and Beverages

Caffeine stimulates the production of stomach acids which, in excess, can cause and upset stomach or heartburn. Heavy caffeine use, generally defined as three or more cups of coffee or the equivalent, daily, may be responsible for an overproduction of stomach acid that leads to digestive distress.

What to Do: Try cutting down on coffee, or switching to decaf.

5. Milk and Dairy Products

The intestines of babies and young children usually produce enough of the enzyme lactase to digest the milk sugar lactose. A majority of people, however, lose the ability to produce lactase as they reach adolescence and adulthood. Without lactase, lactose remains undigested in your intestine. Undigested lactose actually feeds intestinal bacteria that produce acid and gas that result in bloating, pain and diarrhea.

What to Do: Try replacing cow's milk with soy, almond, or coconut milk.

Everyday Tips For Healthier Digestion

Follow this simple advice to better digest any food you eat.

  • Eat smaller meals.
  • Relax while you’re eating.
  • Cook food thoroughly (but do not overcook, or you may lose valuable nutrients or make foods like meat even harder to digest), especially potentially problematic foods like cruciferous vegetables and dried beans.
  • Chew food slowly and thoroughly. Digestion begins in the mouth, where the first digestive enzymes are released.
  • Eat a high-fiber diet, but gradually add more fiber over time so your GI (gastrointestinal) tract can adjust to each increase.
  • Limit the amount of fat in your diet.
  • Be sure to drink plenty of water throughout the day to help move food through your digestive tract. If you suffer from heartburn, drink liquids between, rather than with, meals.
  • Get as much sleep as you need.

Consult a doctor or registered dietitian if symptoms persist over an extended period of time.

Eamonn Quigley, MD reviewed this article.


Quigley, Eamonn M. M., MD, FRCP, FACP, FACG, FRCPI. Email correspondence to author, February 12, 2016.

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