You have probably eaten a meal with someone who was practically finished before you were even a quarter of the way through.  Or maybe you are the one that is always done eating way before anyone else at the table.

Just what effect does this rapid eating have on digestion?  To answer this question, let’s examine the physiology. 

First, remember that the muscles of mastication are skeletal muscles.  The skeletal muscles are involved in our fight or flight reflexes, which are activated by a threat to our physical body.  Some examples of this would be being attacked by a bear or a man with a gun.  The heart rate increases, blood pressure increases, and the glucose is shunted from the liver back into the blood so it’s available for the skeletal muscles.

This all sounds normal and natural, and it is when there is a physical threat to the body. 

However, there is a feedback mechanism built into this wonderful system.  Any time a skeletal muscle is activated rapidly, the feedback mechanism will start to produce adrenaline just as though it was an actual threat.  So, eating rapidly activates the skeletal muscles of the jaw, which activates the sympathetic nervous system, and automatically shuts down digestion because the blood is needed in the skeletal muscles for the fight or flight response to the threat.

So, even though you might’ve already been aware that digestion is not helped by eating too fast, you might’ve thought it was just because you didn’t chew your food and mix it with saliva.  But it’s really a whole lot more serious than that because the entire digestion system shuts down in this “emergency” situation. 

So, the perils of rapid eating are best dealt with by slowing down.  That way, digestion can occur, as eating then (appropriately) becomes the number-one stressor or threat to survival.