A change in your diet can cause stomach pain for a variety of reasons. Indigestion, too much or too little fiber, food intolerance or food allergy can result in digestive distress and can occur when the foods you eat are different than the ones you are accustomed to. In addition, changing how much or how often you eat can also lead to stomach pain. Seek the advice of a dietitian or your health care provider before changing your diet or if a change in diet causes gastrointestinal issues.
A common symptom of indigestion is stomach pain, and this condition can occur when you change your diet. For example, if you eat more protein-rich foods than usual, you might overwhelm the capacity of the protein-degrading enzymes in your stomach and intestines. The resulting backlog of food in your stomach can lead to pain. Even if you keep your food content and quantity the same, changing your meal regimen from, for instance, several small meals to one or two large meals can cause indigestion and stomach pain. Additionally, eating rapidly or eating foods your body is not used to, such as spicy foods, can result in digestive upset.
Fiber is a type of indigestible dietary carbohydrate that contributes to your digestive health even though you do not derive nutrients from it. The University of Nebraska-Lincoln Extension recommends a daily intake of 20 to 35 grams to help regulate your bowel movements. However, changing your diet to rapidly include or exclude fiber can result in gastrointestinal symptoms, such as stomach pain and constipation. Consuming adequate fiber but neglecting to drink enough water to keep the fiber hydrated and moving through your intestines can also result in abdominal pain.
Changing your diet to include a new food your body cannot tolerate can lead to stomach pain. For example, if your intestinal cells do not produce the digestive enzyme lactase or do not make enough of it, you might not be able to digest some or all of the lactose, or milk sugar, you consume from dairy products. As undigested lactose moves through your gastrointestinal tract, bacteria acting on it can produce gas, causing stomach pain and bloating. Lactose intolerance might not be apparent until you change your diet from consuming no dairy products to including them in the foods you eat.
Food allergy differs from food intolerance, because it involves your immune system rather than your digestive system. With a food allergy, your immune cells attack a portion of your digestive system to attempt to rid it of a specific food component perceived as foreign. Similar to food intolerance, the stomach pain resulting from this condition can occur when you change your diet to include a new food.