Have you ever gotten carried away at an all-you-can-eat sushi restaurant? If so, you have likely experienced the extreme onset of sleepiness, otherwise known as a “food coma”. This is a symptom of postprandial fatigue, which is the scientific way of saying after-eating tiredness. It is also referred to as a “post-lunch dip”, where people experience sleepiness, sluggishness, and decreased alertness after eating lunch.
Most of us naturally experience a slight decrease in energy after dining. After all, the body activates the parasympathetic nervous system, which is also known as “rest and digest”, so that we can better absorb nutrients. However, some people experience an extreme amount of fatigue after eating. We consume a meal to gain more energy, so it is incredibly disorienting when we experience less energy afterwards. What could be causing this heightened response?
If you have ever experienced jet lag, you know what it feels like when your body is out of sync. This is caused by a mismatch with your circadian rhythms, which are the body’s internal twenty-four hour clocks that are maintained by exposure to light and dark. When you change the environmental inputs the body receives, such as through irregular eating habits, you alter your circadian rhythm. These rhythms are responsible for the coordination of multiple biological events, such as sleep timing, waking, and glucose metabolism. Glucose is the main energy source we obtain from food. If you fall into a food coma after eating, it could mean that your circadian rhythm is misaligned and is not sending the biological signals you require at correct time.
Glucose metabolism refers to the appropriately timed release of insulin when glucose enters the body. Insulin is the hormone that shuttles glucose from the bloodstream into cells. When your circadian rhythms are disrupted, the body signals the release of insulin much later than when it is needed. Rather than having a peak of insulin in the early afternoon when many people are most active, their insulin peaks much later in the day.
In a healthy individual, consuming a meal is followed shortly by the optimal amount of released insulin. However, there is a problematic outcome that can occur after you consume a meal called hyperglycemia. Hyper means ‘high’ and glycemia means presence of glucose in the blood. Hyperglycemia is associated with multiple diseases such as cardiovascular disease and type II diabetes. Due to a mismatch between your circadian rhythm and environment, insulin is not released at the right timing following dining. After eating, food is broken down into glucose and it floods your bloodstream. Low levels of insulin results in hyperglycemia and a corresponding food coma.
If you are someone who suffers from food comas, there is good news! Adding gentle activity after eating, such as going for a light walk, improves glucose control, which can reduce hyperglycemia. Additionally, you can guide the body’s circadian rhythms by getting early light exposure to multiple wavelengths from the sun. Finally, changing your eating habits by establishing consistent meal times and eliminating snacking could help promote healthy glucose metabolism. It is important to remember that you can synchronize your circadian rhythm to your environment. If you feel as though you suffer intense food comas, it might be worth looking into changing some of your habits to better align your circadian rhythm. Or, it might just be that sloppy Joe’s are just too much for your body to handle at lunchtime on a Monday.
Peer Editors: Nicole Gadda and Molly Parrish