What is a Food Coma and How to Avoid it!

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Despite a good night’s sleep, I still felt dizzy and tired during the afternoon. I found myself losing focus during the lecture and desperate for an afternoon nap. Worse still, my productivity dropped and I had to spend extra time to get things done. This has been the case in my second year since I started my workout routine. I was not aware of the cause until I took a nutritional course that inspired me to do some research. After all, I discovered that what had been bothering me every afternoon was a dietary change I made with the hope to build more muscles, and this dietary change had led to a condition called postprandial somnolence.

Postprandial somnolence, also known as a food coma, is the heavy and sleepy feeling after having a meal. It secretly drained my energy, along with my ability to focus and made me want to sleep. If you are ever stuck in the same situation, please don’t worry! This is a good opportunity for us to learn more about foods and how our body responds to them. After doing some research, I discovered two dietary-related factors that often make me feel heavy and sleepy.

The number one contributor to my food coma was a big increase in the amount of refined carbs (i.e. processed carbohydrates) that I added to my lunchbox. I realized that the white rice and sandwich bread I usually had for lunch are basically all refined carbs. These refined carbs have a pretty high glycemic index and an excessive amount of these led to a rapid spike in my blood glucose level. When my blood glucose level was overly high, it made me feel especially tired and heavy. In addition, my body had to release a huge amount of a hormone called insulin to bring my blood glucose back down to normal. This dramatic and unsustainable change worsened my situation and brought me into a state of reactive hypoglycemia, also know as a sugar crash. In such a case, I felt more tired and sleepy because my body mistakenly thought that there was not enough glucose in my blood (due to the excessive amounts of insulin) and that I was starving (because of the low level of blood glucose).

Drawing by Leonard

The second factor made me struggle a lot because protein-rich foods can also contribute to a food coma. Since I wanted to build muscles, I added more meats and eggs to increase my protein intake. However, protein is made of amino acids and one of them, called tryptophan, is directly associated with sleepiness. Essentially, this amino acid can be convert into serotonin, a neurotransmitter that promotes the body to relax and feel comfortable. Interestingly, serotonin can also turn into melatonin, a sleep hormone that promotes sleep. Although this phenomenon is natural, adding more protein sources or combining them with refined carbs made things worse for me. That was probably the biggest reason why I felt especially tired after lunch because my lunchbox was not only full of white rice but also topped with a lot of chicken!

I started making adjustments to my diet with the hope to improve the situation. After experimenting for a few months, I found switching from refined carbs to whole grain to be a really good strategy! In particular, I found brown rice and whole wheat bread to be better because these carbs have a lower glycemic index compared to their counterparts. If you are a meat lover or on a high-protein diet like I am, I found reducing my meat intake or leaving them until dinnertime to help control food coma in the afternoon.

I hope this blog post provide some insight on how food comas can arise from our diet. Comment below and let us know if you have any tips or tricks to counteract that mid-afternoon slump!



Lehrskov LL, Dorph E, Widmer AM, et al. The role of IL-1 in postprandial fatigue. Mol Metab. 2018;12:107-112. doi:10.1016/j.molmet.2018.04.001

Reactive Hypoglycemia: Causes, How It Feels, Triggers (verywellhealth.com)

Jenkins TA, Nguyen JC, Polglaze KE, Bertrand PP. Influence of tryptophan and serotonin on mood and cognition with a possible role of the gut-brain axis. Nutrients. 2016;8(1):56. doi:10.3390/nu8010056

What is the Glycemic Index? (www.diabetes.ca)

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