When faced with perceived danger, your body's stress response sets off a cascade of physiological symptoms, from hormone changes to blood sugar shifts.
Our adaptive response to stress may lengthen the time it takes for food to move through the digestive tract, slow the production of digestive secretions, and make the muscle contractions involved in digestion sluggish, says Christine Cherpak-Castagna, Ph.D., a nutritionist and adjunct faculty member at the Maryland University of Integrative Health.
Acute stress may also temporarily change the composition of the microbiome1, says Marvin Singh, M.D., an integrative gastroenterologist.
This causes food eaten in a stressed-out state to get a less-than-fair chance of optimal digestion.
For example, let's say you eat a big breakfast, and then while driving to work, someone cuts you off, causing some stress. Later, you struggle with indigestion. "Your body felt that stress, and as a result, your motility was altered, and the food that was sitting in your stomach didn't get out of your stomach as fast as it should have. You feel the effects of that."
Both experts note that these effects might include indigestion, bloating, nausea, heartburn, stomach pain, constipation, or diarrhea. Chronic, long-term stress is also a documented precursor to inflammatory bowel disease2 (IBD) and irritable bowel syndrome (IBS).