Why Do You Feel Tired After Eating and How to Avoid It?

Why Do You Feel Tired After Eating and How to Avoid It?

Does it always drag you to bed after a tasty and rich meal? Fatigue and concentration problems after eating are a relatively common issue. They can be caused by several factors, such as a certain type of food, portion size or mealtime. However, if the tiredness after a meal limits you, there are several solutions to eliminate it. Therefore, look at the most common reasons why food causes fatigue and how to successfully avoid them.

Why Do You Feel Tired After Eating and How to Avoid It?

What causes fatigue after a meal

The first and most fundamental reason for the post-meal fatigue is the type of food your diet contains. The difference is whether it consists of a quality and nutritionally balanced diet or contains ingredients that cause fatigue and exhaustion. Which are they? [1] [2]

Foods rich in protein and carbohydrates

Hormones are responsible for many processes in our body. The feeling of fatigue, which is largely caused by the hormone serotonin, is no exception. It is primarily found in the digestive system, platelets, and central nervous system. It acts as a neurotransmitter, thus helping to transmit nerve signals. However, its biggest benefit is that it affects the process of sleep and thermoregulation. [4] It is protein-rich foods that affect the production of this hormone. This is because the proteins make up the amino acid tryptophan, which promotes the production of serotonin. [3]

What causes fatigue after a meal

Foods rich in carbohydrates have been shown to help absorb tryptophan. However, it is necessary to distinguish between simple and complex carbohydrates in food. Simple sugars and refined carbohydrates break down very quickly in the body into glucose, which the body uses as an energy source immediately. It is therefore not a source of long-term energy. On the other hand, complex carbohydrates are a great source of long-lasting energy, which effectively reduces the feeling of fatigue. [5] Therefore, consider replacing refined carbohydrates, such as white bread, with complex carbohydrates with a higher fiber content and a lower glycemic index, the source of which is whole-grain foods. [6]

Foods rich in protein and carbohydrates

Your optimal daily calorie intake should consist of 45-65% carbohydrates, 20-35% fat and 10-35% protein. [7] Of course, it all depends on your body weight, gender, or daily physical activity. At the same time, it is an optimal income if you want to maintain your weight, when losing weight or gaining weight, this ratio would be different. For a more accurate calculation of the daily intake of macronutrients, try to reach for calorie tables and calculators, which will calculate it for you.

See which foods are rich in the above-mentioned tryptophan:

  • salmon
  • poultry
  • eggs
  • spinach
  • seeds
  • milk
  • soy products
  • cheese

To limit the intake of simple carbohydrates, you should avoid eating following foods:

  • pasta
  • rice
  • white bread
  • cakes, biscuits, donuts, and muffins
  • corn cobs
  • milk
  • sugar and candy

On the contrary, if you want to enrich your diet with complex carbohydrates, the following foods and superfoods are great sources:

Foods rich in fat

Foods rich in fat

According to several studies, consuming too fatty foods can be a trigger of the post-meal fatigue. One of the reasons why it is so is the form of digestion of individual macronutrients in the digestive system. The stomach is the first organ of the digestive tract that is involved in digesting food. It processes carbohydrates first, followed by proteins, and fats are the last nutrients. Therefore, if you take in too much fat into your body, digesting food will take much longer, which will deprive your body of a certain amount of energy. [11] The body needs energy for its basic tasks, such as breathing or the already mentioned digestion. The body gets it in form of calories received. However, if there are not enough of them, the organism suffers and gets tired. Therefore, if you want to avoid fatigue and find out exactly how many calories you need to take to keep your energy expenditure normal, try to use the BMR calculator, which you will learn more about in the article What is basal metabolism and how to calculate BMR?

The second reason for fatigue is consuming the wrong type of fat. We divide fats into saturated and unsaturated. It is the first mentioned type that, when consumed too much, causes digestive problems, and at the same time demonstrably deprives you of energy. [8] This is evidenced by a study in which volunteers were divided into two groups. One group in their diet received 60 g of saturated fats and the other 60 g of unsaturated fats. After eating, the women underwent a 10-minute test focused on performance, attention, and concentration. As a result, it was found that after eating a meal with 60 g of saturated fatty acids, women had on average 11% worse attention. As a result, consumption of saturated fatty acids and heavy fast food dishes can cause fatigue and impaired concentration. [9]

Another study has shown that consuming large amounts of any fat in general causes fatigue. The group that consumed 135 g of fat per day during the study saw a 78% higher increase in fatigue compared to the group that consumed 58 g of fat per day. [10] One of the reasons for this is the effect of fat on sleep apnea. This is a state where you stop breathing at least 20 times during sleep for a short time. These short stops of breathing will interrupt your sleep, preventing you from entering a deep regeneration phase (REM). In fact, people who ate more fat were up to three times more likely to develop apnea. [11] [13]

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The solution to these problems can be the consumption of foods with a lower fat content. Or you can include foods in which unsaturated fats predominate in your diet.

Foods high in saturated fatty acids that you should not consume too much of include:

  • red meat (beef, lamb, pork)
  • chicken skin
  • whole fat dairy products (milk, cream, cheese)
  • butter
  • ice cream
  • fat
  • tropical oils such as palm oil
  • fast food dishes

On the contrary, you can reach for foods rich in unsaturated fatty acids, which will also provide you with other healthy substances. Therefore, reach for these foods:

  • avocado and avocado oil
  • olives and olive oil
  • peanut butter and peanut oil
  • vegetable oils such as sunflower, corn or rapeseed
  • fatty fish such as salmon and mackerel
  • nuts and seeds such as almonds, peanuts, cashews, and sesame seeds

Sour foods

Orexin, in Greek “appetite“, also known as hypocretin, is a neuropeptide that regulates appetite. There are 10,000 to 20,000 orexin-producing neurons in the human brain, found predominantly in the Peripheral region and the lateral hypothalamus. Recent studies suggest that the main role of orexin is to promote alertness. However, it is the consumption of acidic foods that increase the pH in the blood, which suppresses the production of orexin. If the acidity of the blood drops temporarily and the blood or tissues are slightly alkaline, orexin is more likely to be suppressed and fatigue will occur. For this reason, consuming too many acidic or fermented foods is one of the reasons for the formation of fatigue after a meal. [14] [15]

Sweetened beverages cause fatigue after a meal

Researchers also believe that another possible reason why some people feel tired after eating is related to the development of internal inflammation, which also suppresses orexin. [15]

If you do not want to promote fatigue and suppress the neuropeptide that causes alertness, you should avoid foods that increase pH in blood, such as:

  • grains
  • sugar
  • certain dairy products
  • fish
  • processed food
  • fresh meat
  • processed meat, such as canned beef and turkey
  • soda and other sweetened beverages

Regulation of blood sugar levels after meals

Certain types of food regulate blood sugar levels, which can ultimately have the effect of reducing energy after their consumption. These are mostly meals with a medium to high glycemic index (GI). After eating these foods, the body tries to balance the onset of sugar by secreting insulin. It helps the body regulate blood sugar production and stores energy from it for later. However, in this process, insulin also stimulates the production of tryptophan and triggers the release of serotonin and melatonin, two hormones that cause a decrease in energy and fatigue. [17] [18]

Regulation of blood sugar levels after meals

The evidence was also provided by research in which participants in one group consumed foods with a higher GI. The result was a faster increase in fatigue in this group than in the low glycemic diet group. [16]

If you do not want to eat foods with a high GI, you should avoid:

  • sugar and sweet foods
  • sweet drinks
  • white bread
  • potatoes
  • white rice

Portion size

Surely you have already encountered the fact that after eating a larger portion of food or literally after overeating you felt tired. Such states are typical mainly during holidays, celebrations, but more and more often the problem of overeating also occurs every day in ordinary households. The result is the development of obesity, diabetes, or cardiovascular disease. All these problems are also accompanied by one common denominator, which is fatigue. Consumption of large portions increases blood sugar, which leads to the production of insulin and subsequently to fatigue, as described above. [19]

Overeating causes fatigue

Consuming too much food at one time can also cause slower digestion. As we explained in the previous points, digestion significantly affects the body’s energy levels. The more food you eat, the slower the digestion, and your body needs more energy for this process, which causes fatigue. [19]


How you feel immediately after eating can be also affected by your circadian rhythm. It is a natural internal process that regulates the sleep-wake cycle and repeats approximately every 24 hours. The circadian rhythm can be applied to all the biological processes that take place in our body, and thus also eating. [20]

It turns out that the time when you eat really matters. According to research, people have the highest natural resting energy during the day, at 9 o’clock in the morning and 2 o’clock in the afternoon. This explains why you may suddenly feel morning or afternoon fatigue. If you eat at this time, fatigue is more likely to multiply. Therefore, it is recommended to have breakfast before 9 o’clock and to have lunch before 2 o’clock in the afternoon. [20] [21] [22]

Another reason for the correct timing of meals is the elimination of obesity and overeating. This is because if you eat at irregular intervals and only two or three times a day, you may overeat, which results in slower digestion and weight gain. These indicators are common causes of fatigue and exhaustion. Therefore, try eating regularly, at least 5 times a day and smaller portions. This will set up proper digestion and will not burden the body so much. [21] [22]

How to prevent fatigue after eating

We have explained what causes fatigue after a meal. Now is the time to imagine some basic solutions to help you prevent fatigue after eating: [1] [2]

  • do not overdo it with the consumption of proteins and carbohydrates
  • keep optimal daily intake of macronutrients
  • replace simple carbohydrates in your diet with complex ones
  • avoid eating dishes that are too fatty and from fast food chains
  • replace the consumption of saturated fats with a diet containing unsaturated fats
  • eliminate foods that increase blood pH from the diet
  • diets should consist of foods with a lower GI
  • watch the meal portions – calorie tables will also help you with that. However, you should also pay attention to the most common mistakes in counting meals and calories.
  • eat more smaller portions, for example 5 times a day
  • get a quality good night’s sleep
  • try to move more during the day, go for a walk or do some exercise, because physical activity increases energy levels
  • enrich your diet with vitamins and minerals that suppress fatigue and exhaustion, such as vitamin C, selected B-group vitaminsmagnesium and iron
How to prevent fatigue after eating

When setting up your diet, you should not forget the familiar saying “you are what you eat“. So, of course, if you eat foods that cause fatigue, you will feel exhausted. Therefore, consider what your day looks like, how much energy your activities require, and based on these findings, you can figure out what needs to be changed. We believe that our findings summarized in this article will help you make this change.

Do you also feel tired after eating? Share your experience with this problem in the comments because you are definitely not alone in this. If you liked the article, we will be happy if you share it.


[1] Deborah Weatherspoon, Ph.D., R.N., CRNA – Why do people feel tired after eating? – https://www.medicalnewstoday.com/articles/323379

[2] Natalie Butler, RD, LD – Why Do I Feel Tired After Eating? – https://www.healthline.com/health/food-nutrition/why-do-i-feel-tired-after-eating

[3] Mendel Friedman – Analysis, Nutrition, and Health Benefits of Tryptophan – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158605/

[4] Simon N. Young – How to increase serotonin in the human brain without drugs – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2077351/

[5] Complex carbohydrates – https://medlineplus.gov/ency/imagepages/19529.htm

[6] Katherine Marengo, LDN, RD – Simple Carbohydrates vs. Complex Carbohydrates – https://www.healthline.com/health/food-nutrition/simple-carbohydrates-complex-carbohydrates

[7] Gavin Van De Walle, MS, RD – The Best Macronutrient Ratio for Weight Loss – https://www.healthline.com/nutrition/best-macronutrient-ratio

[8] Grant Tinsley, PhD – Is saturated or unsaturated fat better for health? – https://www.medicalnewstoday.com/articles/321655

[9] Ann G. Liu, Nikki A. Ford, Frank B. Hu, Kathleen M. Zelman, Dariush Mozaffarian and Penny M. Kris-Etherton – A healthy approach to dietary fats: understanding the science and taking action to reduce consumer confusion – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5577766/

[10] Annelise A Madison, Martha A Belury, Rebecca Andridge, M Rosie Shrout, Megan E Renna, William B Malarkey, Michael T Bailey, Janice K Kiecolt-Glaser – Afternoon distraction: a high-saturated-fat meal and endotoxemia impact postmeal attention in a randomized crossover trial – https://academic.oup.com/ajcn/article-abstract/111/6/1150/5835679?redirectedFrom=fulltext

[11] Justin J. Patricia; Amit S. Dhamoon – Physiology, Digestion – https://www.ncbi.nlm.nih.gov/books/NBK544242/

[12] Amy Norton – Fatty Foods, Drowsy Days – https://www.webmd.com/diet/news/20160503/fatty-foods-drowsy-days#1

[13] Sleep apnea – https://www.mayoclinic.org/diseases-conditions/sleep-apnea/symptoms-causes/syc-20377631

[14] K. B. Weymann, L. J. Wood, X. Zhu and D. L. Marks – A Role for Orexin in Cytotoxic Chemotherapy-Induced Fatigue – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3951615/

[15] JPuya Yazdi, MD – 12 Natural Factors that May Increase Orexin & Wakefulness – https://selfhacked.com/blog/how-to-increase-orexin-and-decrease-fatigue-naturally/

[16] Ahmad Afaghi, Helen O’Connor, Chin Moi Chow – High-glycemic-index carbohydrate meals shorten sleep onset – https://academic.oup.com/ajcn/article/85/2/426/4649589

[17] Glycemic index for 60+ foods – https://www.health.harvard.edu/diseases-and-conditions/glycemic-index-and-glycemic-load-for-100-foods

[18] Wendy R Russell, Athanasia Baka, Inger Björck, Nathalie Delzenne, Dan Gao, Helen R Griffiths, Ellie Hadjilucas, Kristiina Juvonen, Sampo Lahtinen, Mirian Lansink, Luc Van Loon, Hannu Mykkänen, Elin Östman, Gabriele Riccardi, Sophie Vinoy, Martin O Weickert – Impact of Diet Composition on Blood Glucose Regulation – https://pubmed.ncbi.nlm.nih.gov/24219323/

[19] Secrets of Healthy Eating and Portion Control – https://www.webmd.com/diet/ss/slideshow-serving-sizes

[20] Sophie M.T. Wehrens, Skevoulla Christou, Cheryl Isherwood, Benita Middleton, Michelle A. Gibbs, Simon N. Archer, Debra J. Skene and Jonathan D. Johnston – Meal Timing Regulates the Human Circadian System – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5483233/

[21] Caitlin Dow – How important is meal timing? – https://cspinet.org/tip/how-important-meal-timing

[22] Antonio Paoli, Grant Tinsley, Antonino Bianco and Tatiana Moro – The Influence of Meal Frequency and Timing on Health in Humans: The Role of Fasting – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520689/

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