The concept of dividing daily food intake into three main meals breakfast, lunch, and dinner is quite prevalent. This structure is often recommended to maintain a proper nutrition and provide consistent energy throughout the day. Additionally, dieticians frequently suggest incorporating two snacks, one in the morning and another in the afternoon, `to help manage appetite and prevent overeating during main meals.
Interestingly, the traditional three square meals a day is not a universal standard and is actually a relatively recent development in human history. Different cultures and historical periods have had varying meal patterns, often influenced by lifestyle, work schedules, and availability of food.
As an example, did you know the Ancient Romans typically had only one substantial meal, known as coena, which they consumed around 16:00h? Yes they did and they believed that eating more than once per day was unhealthy. While they did have light, quick meals in the morning (ientaculum) and at noon (prandium), these were quite frugal, light and quick compared to their main meal (Paoli et al., 2019).
How did we come about the names of the three square meals?
The word breakfast literally means “break the night’s fast,” blowing the whistle on it as the first meal after the evening devoted to prayer. During the early medieval period, monks were required to maintain silence during this meal, while one monk read aloud from a religious text. One of the most frequently read texts were the Collationes (compilation) by Giovanni Cassiano (Chasens & Olshansky, 2006).
Interestingly, the Italian word for breakfast, colazione, is derived from the Latin word collations. During the Industrial Revolution, breakfast then gained significance as a crucial meal eaten before heading to work. The modern idea and schedule of dinner gained popularity with the introduction of artificial lighting, which allowed people to have meals both early in the morning and late at night.
As the world industrialized in the 19th century and more people began working outside their homes, fewer families had large midday meals (Zhu et al., 2020). Therefore, the main meal shifted to a later time. By the 20th century, dinner in the evening had become the new norm.
Industrialization also transformed other meals. As dinner moved, lunch appeared as a quick, practical break for refuelling during the day.
What Effects Does Your Meal Frequency Have on Body Weight?
It has been reported that subjects who typically ate six times daily were convinced by McGrath and Gibney to reduce their meal frequency, while those who ate three times daily were persuaded to increase it to six times. This increase in meal frequency led to a significant reduction in total and LDL (low-density lipoprotein) cholesterol levels, although it was accompanied by a decrease in carbohydrate intake. It is known that insulin activates hydroxylmethylglutaryl-CoA (HMG-CoA) reductase, a key enzyme in cholesterol biosynthesis. Studies have shown that a higher meal frequency (nibbling) reduces insulin concentrations compared to three meals daily, likely due to a decrease in cholesterol synthesis. It’s important to note that meal frequency alone cannot fully explain its effects on health outcomes (Zhu et al., 2020).
Why Feel Sleepy after Eating?
Feeling sleepy after eating is known as post-prandial somnolence. When this occurs after lunch, it’s often referred to as the post-lunch dip or the 3 p.m. slump. Following a large holiday meal, it’s commonly called a food coma. A lot of factors may be attributed to wanting to sleep after eating. These include; when you ate, what you to ate, and how much you ate.
When You Ate
The timing of when you eat can affect your energy levels. Eating at inconsistent times can misalign with your body’s natural circadian rhythms, leading to unbalancing energy levels. Eating at irregular intervals can cause blood sugar spikes and crashes, resulting in energy dips. It can reduce metabolic efficiency, making it harder for your body to utilize energy effectively.
How much you ate
Eating too much food can cause post-meal sleepiness. Food rich in protein make people feel sleepier during the day.
What You Ate
Certain nutrients in foods can cause drowsiness after eating. Consuming these foods before bedtime can promote a good night’s sleep. However, if you eat them at lunch, you might feel like taking a nap under your desk (Lucassen et al., 2013).
Some of these nutrients include tryptophan which is high in foods like chicken, egg white, milk and turkey. Tryptophan is an essential amino acid that might make you feel a little sleepy. The body converts tryptophan into serotonin, which is then transformed into melatonin. This process can make you feel sleepy.
Melatonin is a hormone produced by the pineal gland, a small endocrine gland located in the brain. It signals your mind and body to begin winding down for the day, making you feel sleepy.
Studies indicate that carbohydrate-rich meals can cause drowsiness, especially those with a high glycemic index (GI). The glycemic index is a scale that ranks the number of carbohydrates in foods from 0 to 100, indicating how quickly a food causes a person’s blood sugar to rise (Chasens & Olshansky, 2006). Foods with high GI include white rice, potatoes, white bread and so on.
Dehydration can also play a role in post-meal fatigue. Often, people confuse thirst with hunger, resulting in overeating when the body actually needs hydration. Insufficient water intake throughout the day can also reduce alertness and increase fatigue, which may become more obvious after eating.
What happens after eating these foods that can induce sleep?
The type of diet is a big factor. Eating a lot of the foods mentioned above causes the body to undergo several physiological process. High levels of sugars and carbohydrates would be needed to be broken down. This increases the blood sugar level. The body then undergoes homeostasis to stabilize the blood sugar level by secreting insulin. The resulting crash can lead to sudden tiredness.
Insulin is an essential hormone, which helps your body to turn food into energy and regulate blood sugar levels. Think of insulin as the key that opens the doors of the cells of your body. Once insulin opens your cell doors, glucose can leave your blood stream and move into your cells where you use it for energy. Without insulin, glucose cannot get into your cells and instead builds up in your blood. This leads to high blood sugar and diabetes.
We experience low energy bout because we are getting dipping from high insulin levels and it is the body’s way of trying to balance our blood sugar. This is achieved by getting an increase in tryptophan which moves into the brain, metabolizes into serotonin and melatonin which induce sleep. These neurotransmitters (serotonin and melatonin) have effect of regulating our sleep.
How Can we Ease Our Post-Meal Sleepiness?
Practicing portion control and mindful eating is crucial for sustaining energy levels after meals. By being attentive to hunger and fullness signals, we can prevent overeating and the resulting fatigue. Including a variety of complex carbohydrates, lean proteins, and healthy fats in your diet can help maintain stable blood sugar levels and provide sustained energy. Opting for smaller, more frequent meals instead of large, heavy ones can also help avoid the energy slumps that often follow overeating.
Additionally, chewing food thoroughly and eating slowly can enhance digestion and help avoid post-meal drowsiness. Studies show that diets high in vegetables, fruits, and nuts, and low in saturated fats, processed foods, and desserts, are linked to lower levels of daytime sleepiness.
Light is a key circadian signal, so taking a walk in the sunshine or spending 30 minutes in front of a light box can help reduce or prevent post-meal fatigue. If your schedule permits, engaging in moderate-intensity exercise, such as speed walking or biking, before post-meal tiredness sets in can boost energy and kick off fatigue.
Stay hydrated. Consuming ample water throughout the day can enhance alertness and prevent sleepiness. Drinking water before, during, and after meals helps in preventing dehydration and supports effective digestion. Some people find that sipping herbal tea or infused water offers a refreshing alternative to plain water while enhancing hydration.
Conclusion
Feeling sleepy after eating is a complex situation influenced by various factors, such as meal composition, lifestyle habits, and individual psychology all plays a role in how our bodies respond to food and energy levels. Balancing these elements can help maintain steady energy and reduce fatigue throughout the day. Paying attention to your body's cues and making smart choices about what you eat, drink, and how you move can significantly boost your alertness post-meal.
If you are struggling to stay alert and focus during the day, do not overlook the power of a nap.
References
Chasens, E. R., & Olshansky, E. (2006). The experience of being sleepy while managing type 2 diabetes. Journal of the American Psychiatric Nurses Association, 12(5), 272–278. https://doi.org/10.1177/1078390306295086
Lucassen, E. A., Zhao, X., Rother, K. I., Mattingly, M. S., Courville, A. B., de Jonge, L., Csako, G., & Cizza, G. (2013). Evening Chronotype Is Associated with Changes in Eating Behavior, More Sleep Apnea, and Increased Stress Hormones in Short Sleeping Obese Individuals. PLoS ONE, 8(3). https://doi.org/10.1371/journal.pone.0056519
Paoli, A., Tinsley, G., Bianco, A., & Moro, T. (2019). The influence of meal frequency and timing on health in humans: The role of fasting. Nutrients, 11(4), 1–19. https://doi.org/10.3390/nu11040719
Pi-Sunyer, F. X. (2002). The obesity epidemic: Pathophysiology and consequences of obesity. Obesity Research, 10(SUPPL. 2). https://doi.org/10.1038/oby.2002.202
Tada, Y., Yoshizaki, T., Tanaka, I., Kanehara, R., Kato, M., Hatta, N., Hida, A., & Kawano, Y. (2018). Higher energy intake at dinner decreases parasympathetic activity during nighttime sleep in menstruating women: A randomized controlled trial. Physiology and Behavior, 194(2017), 252–259. https://doi.org/10.1016/j.physbeh.2018.06.010
Zhu, B., Chen, X., Park, C. G., Zhu, D., & Izci-Balserak, B. (2020). Fatigue and Sleep Quality Predict Eating Behavior among People with Type 2 Diabetes. Nursing Research, 69(6), 419–426. https://doi.org/10.1097/NNR.0000000000000447
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