The natural composition or preparation of some foods makes them difficult to digest and can cause embarrassing flatulence, bloating, cramps and diarrhea. A side note - food allergies or food sensitivities can also increase the number of problem foods.
Wheat, Barley and Rye Products
Wheat, barley and rye contain gluten, which is a protein some people find difficult to digest. Foods that contain these grains can include pasta, bread, baked goods and cereal, as well as less-suspect foods such as gravy, salad dressings, sauces, beer, broth, fried foods and seasoned snack foods. Gluten sensitivity causes symptoms such as lack of energy, mental fatigue, bloating, diarrhea and abdominal cramps. Eating a gluten-free diet relieves the symptoms, but can cause nutritional deficiencies. Eating a gluten-free diet that includes milk, yogurt, cheese, eggs, meat, poultry, fish, fruits, vegetables, legumes and gluten-free grains, such as quinoa and millet, can help those who have gluten sensitivity maintain adequate nutrition.
Milk and Milk Products
Lactose, which is also called milk sugar, presents digestive problems for some adults. During the digestive process, an enzyme called lactase breaks down lactose into simple sugars your body can absorb. Lactase production begins to slow down by age 2. Without enough lactase, undigested lactose passes into your large intestine, where bacterial fermentation produces gas, bloating and stomach cramps. To combat the symptoms of lactose intolerance, avoid foods such as milk, soft cheeses, butter, ice cream as well as lactose-containing prepackaged foods like creamed vegetables, instant mashed potatoes, pudding, custard, cakes and chocolate. Alternatively, you can buy lactose-free products, take lactase tablets with your first bite of lactose-containing foods or add lactase drops to milk.
Foods That Cause Acid Reflux
When you eat, the food travels down your esophagus into your stomach. Some foods cause digestive difficulties because they relax or weaken the lower esophageal sphincter, which is also called the LES. Located at the bottom of your esophagus, the LES prevents acid reflux, which occurs when food and stomach acid back up from your stomach into your esophagus. Symptoms of acid reflux include heartburn, inflamed vocal cords, chronic cough and pain that mimics the chest pain associated with heart problems, according to the UC Davis Health System. Foods that can weaken or relax your LES include fatty, fried foods, citrus fruits, tomatoes, chocolate, garlic, onions, spicy foods and caffeinated beverages.
Soluble Fiber
Soluble fiber makes foods such as beans, oat bran, apples, citrus fruits and vegetables difficult to digest in the small intestine. Because the small intestine does not have the enzymes needed to digest soluble fiber, these foods pass undigested into your large intestine for digestion and absorption by gas-producing bacteria. Consuming large amounts of foods containing soluble fiber produces intestinal gas and bloating.
Saying all the above is not to say you shouldn't eat these foods, it is rather to create conciseness when consuming such foods, so that you are able to manage your activities, your eating timings etc, to allow your body to work its magic :).