You should avoid eating when stressed. Digestion is controlled by a system composed of hundreds of millions of nerves that communicate with the central nervous system. When stress activates the "flight or fight" response it affects the contractions of the digestive muscles, and decreases secretions needed for digestion. Stress can increase stomach acid, causing indigestion and/or cause your colon to react in a way that results in diarrhea or constipation.
Planning your meals in advance - so that you don't have to eat while driving or race from work day to crowded grocery store to home - is a good way of avoiding stress at mealtimes.