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How to Stop Feeling Tired After Eating and Beat Afternoon Slumps

Lunch is supposed to give you the energy you need to power through your afternoon. But what if instead, it makes you feel more tired?

Reviewed by Gina Brown, ND

If this sounds like you, know you are not alone. 1 in 3 Americans report suffering from excessive daytime sleepiness. In this article, we break down why you might be feeling this way, and what you can do to overcome it.  

While fatigue following a meal could just mean your body is taking some much-needed energy for digestion, it might also be signaling that something is off. Post-meal fatigue describes the drop in energy levels someone might experience following a meal, but the medical term is postprandial somnolence .

Some researchers think feeling tired after a meal is an adaptive mechanism that helped our ancestors survive. When food was scarce, it was essential to stay alert and awake when you were hungry, to help locate food. Commonly called vigilance signals, this protective mechanism is thought to disperse once you get enough food.

Natural and predictable shifts in energy throughout the day can also be tied to the afternoon slump. But, when combined with a lunchtime meal, this effect can become even bigger. In some situations, post-meal fatigue can be normal (think Thanksgiving dinner), but regular dips in energy after meals can hint towards negative health issues that deserve attention.

One of the contributors to post-meal fatigue is suboptimal blood sugar control and glucose intolerance. This is why diabetics can suffer worse from post-meal fatigue than healthy people. But it can happen to anyone – whether you have an official diagnosis or not. In fact, it is very, very common, but not healthy.

Note: If you have diabetes, please get medical attention to regulate your blood sugar. This article is for non-diabetics and “healthy” people who want to further optimize their health to feel steady energy throughout the day. This article does not talk about any treatment or cure for any disease.

The good news is that there are many things you can do to help prevent it, once you figure out what factors may be contributing.  

5 Causes of Post-meal Fatigue and Afternoon Sleepiness

Those feelings of sleepiness after a meal usually come on 30 minutes to 1 hour after your lunch. To make things worse, it can last hours, impacting your work productivity and causing the dreaded loss of energy in the afternoon. You may better understand this experience as a “food coma”. But what might cause this post-lunch energy dip?

Researchers are not exactly sure. Likely, it is a combination of multiple things – meal composition, stimulant intake, hormones, baseline health status, and many more. Here we focus on a few potential causes that might be contributing to your fatigue experience.

1) High Blood Sugar and Inflammation From Food Raise Oxidative Stress

Sugar usually gives you energy – right? Technically, yes! Glucose (the technical name for sugar) is your body’s preferred energy source. Cells in your body use it to carry out many different functions in your body.

But glucose is an oxidizing sugar. When blood sugar stays high over long periods of time, it can increase oxidative stress and inflammation. Combined, these can be a cause of post-meal fatigue. Let’s break down how this can happen:

  • Blood sugar rises following all meals, especially meals heavy in carbohydrates. Whereas high-protein and high-fat meals raise blood sugar to a lesser extent.
  • Poor diet, excess sugar, and even stress can contribute to persistent high blood sugar levels and less efficient insulin response. When your blood sugar stays high chronically, it can trigger inflammation and the production of reactive oxygen species (ROS).
  • Excess blood sugar temporarily increases oxidative stress and inflammation in your blood and body [R9]. These can damage cells, proteins, and other molecules in your body. Oxidative stress also tends to inhibit mitochondria function, making you tired.
  • High blood sugar increases insulin, which helps bring more tryptophan into the brain. Tryptophan provides a backbone for serotonin and melatonin, which can increase drowsiness. This is especially the case if you pair a high-carb meal with a high-tryptophan food.
  • High oxidative stress can inhibit orexin neurons. Orexins are neurotransmitters that promote wakefulness and maintain alertness

Collectively, all these processes contribute to feelings of sleepiness and fatigue, especially following meals that are higher in carbohydrates. Your body’s ability to process and use glucose from the meal, alongside oxidative stress levels, can leave you feeling tired and mentally foggy.

2) Minor Inflammation From Food

Inflammatory cytokines like IL-1 and TNF-alpha are sleep-drive molecules that make you sleepy at night and allow you to achieve deep sleep . The fatiguing effects of inflammation also explain why being sick makes you feel tired and want to sleep more. 

Now, mild and temporary inflammation from diet and lifestyle sources, such as food, can contribute to the afternoon slump. If you notice that some foods make you feel more sleepy than others, there might also be some food sensitivities or intolerances that sap your post-meal energy.

It is a good idea to figure out which foods are doing this to you (more on this later), so you can be in charge of your afternoon energy and make informed food choices. 

3) Reactive Hypoglycemia 

High-carb meals can trigger an excessive insulin response, causing a quick drop in blood sugar levels. When blood sugar drops too low following a meal, we call it reactive hypoglycemia. Often, they are both happening, one after the other.

Here’s how reactive hypoglycemia can cause post-meal fatigue:

  • High blood sugar increases oxidative stress, leading to post-meal fatigue and brain fog.
  • With too much blood sugar, too much insulin is secreted following a meal. This causes a rapid uptake of glucose from the blood, and a rapid drop in blood sugar levels. This can cause areas of your body, such as your brain, to lack the continuous energy it needs

Since the brain needs glucose for energy, too little in circulation can manifest in feelings of sleepiness and fatigue. It might also cause “brain fog” symptoms, such as issues with concentration and mental clarity.

  • Once you experience a drop in blood sugar, it can take time for your body to stabilize blood sugar levels and regain energy. This delayed recovery can cause post-meal fatigue to persist up to hours following a meal 

You might think that an easy solution to this would be to consume another high-carb food to quickly raise blood sugar. However, this can lead to a cycle of blood sugar spikes and crashes, making your feelings of fatigue worse over time. Instead, proteins and fats tend to be better at helping you stabilize your blood sugar and avoid the blood sugar rollercoaster.

4) Suboptimal Digestion 

Researchers have hypothesized that you might feel tired following a meal because your body needs to slow down everything else and prioritize resources for digestion. When you eat, blood is shuttled to your digestive tract, where it can support the breakdown and absorption of nutrients

This can cause changes to blood flow to the brain, causing you to feel more tired. Plus, digesting food and moving it along requires energy. 

When your body does not digest food efficiently, this effect might become even worse. There are multiple things that can cause suboptimal digestion, let’s unpack a few:

  • Ineffective digestive enzyme function: your body produces and relies on digestive enzymes to help break down food into smaller molecules that your body can then absorb. When your body does not have enough enzymes, or they do not function as well as they should, such as from enzyme inhibitors, you’ll feel sluggish after meals. 

This could also mean your body takes longer or fails to completely digest and absorb your foods.

  • Unbalanced gut microbiome: the bacteria in your gut help break down food to extract nutrients. To do this effectively, there needs to be enough diversity of good gut bacteria. 

In a disrupted balance, like too many suboptimal strains, food cannot be absorbed properly. To top it off, some suboptimal gut bacteria can also produce compounds that can contribute to fatigue.

  • Nutrient deficiencies: when digestion does not work as well as it should, you might not be able to extract all the vitamins and minerals you need from food. You need micronutrients to produce energy, so suboptimal levels of these nutrients could mean your cells struggle to produce enough energy.
  • Digestive discomfort: Post-meal discomforts like bloating and gas can contribute to fatigue. All these experiences can be both mentally and physically draining on the body and contribute to post-meal fatigue. They can also disrupt how well you sleep during the night, worsening your symptoms.

Combined, all these factors can worsen the afternoon slump, leaving you feeling tired and impacting your productivity.

5) Morning Caffeine and Stimulants Wearing Off

Ah, that beloved morning coffee! Caffeine, the compound found in coffee and other beverages like tea, can have many health benefits, including making you feel more alert. While it is very effective, its effects can be short-lived and may do you more harm than good when it comes to all-day energy.

Its major downside is how fast it is metabolized in the body. Once you drink that morning cup of joe, it is rapidly absorbed. In fact, 99% of the caffeine is in circulation within 45 minutes after ingestion. This makes it extremely effective at giving you that initial burst of energy.

Relying on caffeine as a crutch for alertness can be helpful, but what goes up must come down. It is quickly metabolized from your body, somewhere in the range of 2-5 hours – meaning that these awakening effects only last a couple of hours at best.

Another factor is that, despite its quick metabolism, some caffeine can hang out in your body once the noticeable effects have dissipated. This might impact how well you can fall asleep at night and make you feel even more tired the next day. You can see how this quickly becomes a vicious cycle.

For those seasoned coffee drinkers, tolerance can also be a concern. When consumed regularly, your body increases the number of adenosine receptors. Adenosine, naturally made in your body, promotes feelings of relaxation and sleepiness. 

When caffeine binds to them, it prevents natural adenosine from being able to bind – this is why caffeine can make you feel more alert. So, with more adenosine receptors, caffeine should be even more effective, right?

Wrong! More receptors means that you might need even more coffee to bind all these new receptors which may actually lead to increased fatigue levels over time. Otherwise, you might find yourself more tired and foggy. Higher doses of caffeine can also cause side effects, such as anxiety, fast heartbeat, and shakiness.

The solution here is to either stop relying on caffeine or to use caffeine wisely to minimize tolerance and other side effects.

6 Ways to Finally Stop Feeling Tired After Eating and Beat Afternoon Slumps

Optimize Your Blood Sugar Control

Keeping blood sugar levels as steady throughout the day as you can is key to mitigating post-meal fatigue. 

For most people, this means focusing your diet around proteins and fibers, with some healthy fats and low glycemic impact carbs. Treat carbs as a condiment rather than as the main component of your meal, and let vegetables be the star of every meal, including breakfast. Keep to 3 square meals with no snacking in between.

There is a small percentage of the population who are more sensitive and tend to get low blood sugar. These people may need smaller, more frequent low-glycemic meals to prevent excessive fluctuations. 

With the rise of devices that can monitor blood sugar, you can also assess your own unique postprandial response to certain foods, which can give you more insight into how your body controls blood sugar.

If you will occasionally enjoy high-carb meals, consider a blood sugar support supplement. Blood Sugar Breakthrough contains a unique formulation of ingredients that can help you stabilize blood sugar levels. It works by:

  • Supporting biochemical and cellular pathways involved in blood sugar responses
  • Counteracting oxidative damage from high blood sugar within normal range
  • Balancing the hormones involved in these processes
  1. Experiment to Find Out Your Food Sensitivities and Foods That Make You More Tired

If you think that food allergies or intolerances might be contributing to your afternoon slump, working to identify them can be useful.

One strategy often used is implementing an elimination diet. Start by keeping a food journal, which can help you figure out which foods might be causing your symptoms. Then try eliminating identified foods for a 4-week period and re-introduce them one at a time to see if any symptoms come back.

Mono-meals might also be helpful and involve eating only one food or food group at each meal. For example, only chicken at breakfast, fruit at lunch, or vegetables at dinner. While this might be helpful for figuring out potential food intolerances or re-building energizing meals from the ground up, it is not sustainable and extremely limiting.

While an imperfect science, tracking your food intake can be a game changer in helping you understand why you might get that afternoon slump. Using an app to track which foods you eat and your energy levels allows you to draw some parallels on these connections, and help you make more informed lunch choices.

Optimize Your Sleep

Getting a solid night of shut-eye is one of the best tools you have to improve afternoon energy and beat post-meal fatigue. When you are well rested, everything functions better – including digestion.

Those who don’t get enough sleep can contribute to many of the above-mentioned factors that can worsen your symptoms, including suboptimal glucose tolerance and a greater need for caffeine. Focus on proper sleep hygiene and the recommended 8 hours per night to maximize your benefit.

Taking a brief, 15-minute nap after lunch can also help. In one study, those who did take time to recharge reduced their fatigue levels, and improved alertness and performance. It is best to keep it short and sweet – anything longer than 20 minutes might give you sleep inertia, making you feel even more tired and could interfere with your regular sleep schedule.

Optimize Your Digestion

Making sure your digestive tract is functioning well can help optimize energy levels and nutrient absorption. One often overlooked strategy when it comes to digestion is mindful eating.

This involves slowing down for meals, chewing food thoroughly, and focusing on enjoying your meal. It works by making sure your nervous system is in the “rest and digest” phase, which promotes enzyme functions and food movement through the digestive tract.

Suboptimal enzyme production, low stomach acid, and poor bile flow can definitely play a role, especially with aging. So consider adding the following supplements.

HCL Breakthrough increases your stomach acidity and provides enzymes that work in acidic conditions. By helping to restore healthy stomach acid levels, you can better break down your foods and absorb amino acids and minerals

Stomach acid opens up the structure of your food, allowing other enzymes to access it later in the digestive process. The acidity also triggers gut movement. Overall, HCL Breakthrough will help smoothen the digestive process and help move things along faster, minimizing heaviness and post-meal fatigue.

MassZymes contains full-spectrum digestive enzymes with the highest concentration of proteases that can work even at suboptimal gut pH. It contains a variety of plant-based digestive enzymes that can break down all kinds of food substances, even some that may cause minor gut irritation. 

This enzyme effectively eliminates post-meal bloating, sluggishness, heaviness, and other post-meal discomfort. 

Optimize Your Stimulants

Relying on stimulants as a band-aid every afternoon is like a high-interest energy loan from your body–this tends to create a vicious cycle. If you can help it, stimulants shouldn’t be your first-line solution to your afternoon slump. 

You first want to troubleshoot post-meal fatigue by looking at all possible causes. Then, use stimulants to maximize your performance or on occasions where you really need it.

To maximize the benefits of coffee, it’s best to wait an hour or two after waking up before having a cup. You can assess how tired you are, and dose yourself accordingly. Caffeine works by blocking adenosine receptors, so it’s more effective when you have some adenosine in your brain, 1 – 2 hours after waking.

Be sure to avoid any caffeinated beverages in the afternoon so as not to disrupt sleep. To keep caffeine effective long-term, either stop taking it (or drink decaf) on the weekends or one week each month. 

Another good news is that caffeine or coffee aren’t the only stimulants or energizing substances you can use. It might be time to explore and experiment, from Yerba mate to medicinal mushrooms and B vitamins. 

All of them work a little differently (other than blocking adenosine) and have different timelines of absorption and elimination from your body. Stacking, such as by adding caffeine with theanine, can also change the half-life and create some synergistic benefits.

The short half-life of caffeine and how the energy it provides tends to drop off led Mr. Noots to formulate layered stimulant blends like Aquaspark. He combines various stimulants with amino acids and theanine to deliver smooth and long-lasting energy that allows you to be productive all day. 

You can experience these benefits by trying Nootopia blends, especially Brain Flow and Apex.

Many adaptogens also have stimulant properties, but they work by supporting your stress response axis, balancing your oxidative stress, and supporting the brain. 

Take a Walk

Engaging in gentle physical activity after lunch can help your body control blood sugar and give you a good boost of endorphins and brain blood flow to increase afternoon energy. Bonus points if you do an outdoor activity, as blue light can naturally help increase mental function and alertness.

It does not have to be long, or even intensive. 10-15 minutes will still provide the benefits of increased energy levels.


While post-meal fatigue is very common, it’s not healthy or optimal. Working to identify and address underlying issues can help you regain your afternoon energy and avoid that post-lunch slump. Often, solutions are simple – small changes to diet and lifestyle can have a major impact!

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  1. Jaussent I, Morin CM, Ivers H, Dauvilliers Y. Incidence, worsening and risk factors of daytime sleepiness in a population-based 5-year longitudinal study. Sci Rep. 2017;7(1). doi:10.1038/s41598-017-01547-0
  2. Orr WC, Shadid G, Harnish MJ, Elsenbruch S. Meal composition and its effect on postprandial sleepiness. Physiol Behav. 1997;62(4):709-712. doi:10.1016/s0031-9384(97)00012-7
  3. Gallagher T, You YJ. Falling asleep after a big meal: Neuronal regulation of satiety. Worm. 2014;3(1):e27938. doi:10.4161/worm.27938
  4. Boege HL, Bhatti MZ, St-Onge MP. Circadian rhythms and meal timing: impact on energy balance and body weight. Curr Opin Biotechnol. 2021;70:1-6. doi:10.1016/j.copbio.2020.08.009
  5. Fritschi C, Quinn L. Fatigue in patients with diabetes: A review. J Psychosom Res. 2010;69(1):33-41. doi:10.1016/j.jpsychores.2010.01.021
  6. 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
  7. Makowski MS, Shanafelt TD, Hausel A, Bohman BD, Roberts R, Trockel MT. Associations between dietary patterns and sleep-related impairment in a cohort of community physicians: A cross-sectional study. Am J Lifestyle Med. 2021;15(6):644-652. doi:10.1177/1559827619871923
  8. Zhou Y, Chen Q, Luo X, Li L, Ru T, Zhou G. Does bright light counteract the post-lunch dip in subjective states and cognitive performance among undergraduate students? Front Public Health. 2021;9. doi:10.3389/fpubh.2021.652849
  9. Fiorentino T, Prioletta A, Zuo P, Folli F. Hyperglycemia-induced oxidative stress and its role in diabetes mellitus related cardiovascular diseases. Curr Pharm Des. 2013;19(32):5695-5703. doi:10.2174/1381612811319320005
  10. Mouri M, Badireddy M. Hyperglycemia. StatPearls Publishing; 2023.
  11. Holesh JE, Aslam S, Martin A. Physiology, Carbohydrates. StatPearls Publishing; 2023.
  12. Freeman AM, Acevedo LA, Pennings N. Insulin Resistance. StatPearls Publishing; 2023.
  13. Daniel PM, Love ER, Moorhouse SR, Pratt OE. The effect of insulin upon the influx of tryptophan into the brain of the rabbit. J Physiol. 1981;312(1):551-562. doi:10.1113/jphysiol.1981.sp013643
  14. Rotondo M, Honisch C, Tartaggia S, Ruzza P. Circular dichroism study of orexin B under oxidative stress conditions. Molecules. 2023;28(2):484. doi:10.3390/molecules28020484
  15. Krueger J. The role of cytokines in sleep regulation. Curr Pharm Des. 2008;14(32):3408-3416. doi:10.2174/138161208786549281
  16. Altuntaş Y. Postprandial Reactive Hypoglycemia. SiSli Etfal Hastan Tip Bul / Med Bull Sisli Hosp. Published online 2019. doi:10.14744/semb.2019.59455
  17. Ahmed FW, Majeed MS, Kirresh O. Non-Diabetic Hypoglycemia. StatPearls Publishing; 2023.
  18. Blaak EE, Antoine JM, Benton D, et al. Impact of postprandial glycaemia on health and prevention of disease. Obes Rev. 2012;13(10):923-984. doi:10.1111/j.1467-789x.2012.01011.x
  19. Wells AS, Read NW, Uvnas-Moberg K, Alster P. Influences of fat and carbohydrate on postprandial sleepiness, mood, and hormones. Physiol Behav. 1997;61(5):679-686. doi:10.1016/s0031-9384(96)00519-7
  20. McNay EC, Cotero VE. Mini-review: Impact of recurrent hypoglycemia on cognitive and brain function. Physiol Behav. 2010;100(3):234-238. doi:10.1016/j.physbeh.2010.01.004
  21. Warren RE, Frier BM. Hypoglycaemia and cognitive function. Diabetes Obes Metab. 2005;7(5):493-503. doi:10.1111/j.1463-1326.2004.00421.x
  22. Ishizeki A, Kishino T, Ogura S, et al. Influence of breakfast on hemodynamics after lunch – a sonographic evaluation of mesenteric and cervical blood flows. Clin Physiol Funct Imaging. 2019;39(3):226-229. doi:10.1111/cpf.12556
  23. van der Steen WJ. Chronic fatigue syndrome: a matter of enzyme deficiencies? Med Hypotheses. 2000;54(5):853-854. doi:10.1054/mehy.1999.0964
  24. Zuvarox T, Belletieri C. Malabsorption Syndromes. StatPearls Publishing; 2023.
  25. Boolani A, Gallivan KM, Ondrak KS, et al. Trait energy and fatigue may be connected to gut bacteria among young physically active adults: An exploratory study. Nutrients. 2022;14(3):466. doi:10.3390/nu14030466
  26. Withrow D, Bowers SJ, Depner CM, González A, Reynolds AC, Wright KP Jr. Sleep and circadian disruption and the gut microbiome-possible links to dysregulated metabolism. Curr Opin Endocr Metab Res. 2021;17:26-37. doi:10.1016/j.coemr.2020.11.009
  27. Matenchuk BA, Mandhane PJ, Kozyrskyj AL. Sleep, circadian rhythm, and gut microbiota. Sleep Med Rev. 2020;53(101340):101340. doi:10.1016/j.smrv.2020.101340
  28. Azzolino D, Arosio B, Marzetti E, Calvani R, Cesari M. Nutritional status as a mediator of fatigue and its underlying mechanisms in older people. Nutrients. 2020;12(2):444. doi:10.3390/nu12020444
  29. Montoro-Huguet MA, Belloc B, Domínguez-Cajal M. Small and large intestine (I): Malabsorption of nutrients. Nutrients. 2021;13(4):1254. doi:10.3390/nu13041254
  30. Voigt RM, Forsyth CB, Keshavarzian A. Circadian rhythms: a regulator of gastrointestinal health and dysfunction. Expert Rev Gastroenterol Hepatol. 2019;13(5):411-424. doi:10.1080/17474124.2019.1595588
  31. Vernia F, Di Ruscio M, Ciccone A, et al. Sleep disorders related to nutrition and digestive diseases: a neglected clinical condition. Int J Med Sci. 2021;18(3):593-603. doi:10.7150/ijms.45512
  32. Institute of Medicine (US) Committee on Military Nutrition Research. Pharmacology of Caffeine. National Academies Press; 2001.
  33. Holtzman SG, Mante S, Minneman KP. Role of adenosine receptors in caffeine tolerance. J Pharmacol Exp Ther. 1991;256(1). Accessed October 5, 2023.
  34. O’Callaghan F, Muurlink O, Reid N. Effects of caffeine on sleep quality and daytime functioning. Risk Manag Healthc Policy. 2018;11:263-271. doi:10.2147/rmhp.s156404
  35. Murray A, Traylor J. Caffeine Toxicity. StatPearls Publishing; 2023.
  36. Wood RA. Diagnostic elimination diets and oral food provocation. In: Food Allergy: Molecular Basis and Clinical Practice. Vol 101. S. Karger AG; 2015:87-95.
  37. Takahashi M, Fukuda H, Arito H. Brief naps during post-lunch rest: effects on alertness, performance, and autonomic balance. Eur J Appl Physiol. 1998;78(2):93-98. doi:10.1007/s004210050392
  38. Guilliams TG, Drake LE. Meal-time supplementation with betaine HCl for functional hypochlorhydria: What is the evidence? Integrative Medicine: A Clinician’s Journal. 2020;19(1):32.
  39. Anas Sohail A, Ortiz F, Varghese T, et al. The cognitive-enhancing outcomes of caffeine and L-theanine: A systematic review. Cureus. Published online 2021. doi:10.7759/cureus.20828
  40. Tosini, G., Ferguson, I., & Tsubota, K. Effects of blue light on the circadian system and eye physiology. Molecular vision. 2016;(22):61-72.
  41. Solomon TPJ, Tarry E, Hudson CO, Fitt AI, Laye MJ. Immediate post-breakfast physical activity improves interstitial postprandial glycemia: a comparison of different activity-meal timings. Pflugers Arch. 2020;472(2):271-280. doi:10.1007/s00424-019-02300-4
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