It has been a common daily challenge that most of us tend to face while battling the after-meal drowsiness that tempts us to take a nap. Though a meal adds to caloric consumption that must provide energy, the body demands a state of rest instead of feeling energized. This state has been given several alternative terminologies including: “Postprandial somnolence,” “cloud food,” “carbohydrate coma,” or “food coma.”

Post-meal sleep inducers:

• Insulin action: Consuming a meal contributes to an increase in blood sugar. Since the blood glucose levels shoot up, the pancreatic beta cells are stimulated by the hypothalamus in response to the release of the insulin hormone. Insulin suppresses blood sugar by breaking it down, and the body begins to feel less energetic and sleepy.
  
• Orexin: A study conducted by Lee and co-researchers in 2004 revealed that Orexin neurons, which produce a protein called orexin, are extremely sensitive to glucose levels in the blood. Hence, after a meal, the glucose levels rise and moderate wakefulness.
  
• Tryptophan rise: In response to increased insulin production, another mechanism results to produce tryptophan. Tryptophan in increased amounts is transported to the brain where serotonin and melatonin are produced. These induce sluggishness and sleep.
  
• Energy expenditure: An appreciable amount of energy is spent in an attempt to metabolize the food. This may give a feeling of laziness and sleepiness especially when high-calorie foods are consumed, as it requires higher energy expenditure to support the process of digestion. However, feeling excessively fatigued and experiencing symptoms like diarrhea or constipation can be indicators of other health issues and must be taken to the doctor’s notice.
  
• Break: A meal may simply give a break after long hours of work and provide some time to feel tired after thinking about the work done and the pending work that needs to be done. This natural psychology can help one feel tired and thus sleepy.
  
• Circadian rhythms: This explains the natural biological clock that induces sleep at 2:00 AM to 4:00 AM and again between 2:00 PM and 4:00 PM in the case of adults. The transition occurs during teenage years, which tend to disturb the sleep patterns initially. Circadian rhythms can, however, depend on weather conditions or work schedules that could influence the biological clock.
  
• Caffeinated beverages: Caffeine-containing beverages, such as coffee, tea, or soda, can induce sleep by blocking the normal function of the brain hormones.
  
• Alcohol: If the meal has a place for some alcohol, it could lead to headaches, dizziness, confusion, and sleepiness. This is a short-term result, however.
  
• Diet: High energy foods may need higher energy expenditure. However, a study by Orr and co-authors in 1997 concluded that the dietary constituents do not play a role in determining postprandial sleepiness. However, the state of food matters. The study stated that liquids in the meal are more sleep inducing as compared to the solids.
  

Consuming foods low in sugar can help prevent the elevation of blood glucose, insulin, tryptophan, and serotonin levels. On the other hand, including foods rich in complex carbohydrates, like fiber, which ease digestion and promote a slow release of sugar into the bloodstream can be a good idea. Having small meals at frequent intervals in place of large meals spaced far apart can help keep meals light and at the same time, prevent the feeling of being inactive and sleepy.

References:

Davila, D.G. (2009 Dec). Food and Sleep. Retrieved from http://sleepfoundation.org/sleep-topics/food-and-sleep?page=0%2C0

Sleep Drive and Your Body Clock. Retrieved from http://sleepfoundation.org/sleep-topics/sleep-drive-and-your-body-clock

Missimer, R. Do You Feel Tired After Eating? Retrieved from http://www.healthguidance.org/entry/11502/1/Do-You-Feel-Tired-After-Eating.html

Bazar, K. A., Yun, A. J., & Lee, P. Y. (2004). Debunking a myth: neurohormonal and vagal modulation of sleep centers, not redistribution of blood flow, may account for postprandial somnolence. Medical hypotheses, 63(5), 778-782. Retrieved from

http://www.ncbi.nlm.nih.gov/pubmed/15488646

Orr, W. C., Shadid, G., Harnish, M. J., & Elsenbruch, S. (1997). Meal composition and its effect on postprandial sleepiness. Physiology & behavior, 62(4), 709-712. Retrieved from

http://www.ncbi.nlm.nih.gov/pubmed/9284488