Why do you get tired after meals? This post will explain why.
- Fatigue is From The Hypothalamus (Mainly)
- Post Meal Fatigue is a Metabolic Problem
- 13 Reasons You Get Tired After Meals
- 1) Carbs and Glucose (by suppressing orexin)
- 2) Inflammation (by suppressing orexin)
- 3) Acidity, Orexin, and Post-Meal Fatigue
- 4) ATP and Orexin
- 5) Leptin and Post-Meal Fatigue
- 6) Low NAD+/SIRT1 and Post-Meal Fatigue
- 7) Less Blood Flow to the Brain
- 8) Parasympathetic Activation (rest and digest)
- 9) Circadian Rhythms and Fatigue
- 10) CCK and Post-Meal Fatigue
- 11) Insulin, BCAAs, and Tryptophan
- 12) Insulin-Induced Low Potassium
- 13) Cannabinoids and Orexin
- Top Ways to Prevent Post-Meal Fatigue
- SelfDecode and SelfHacked Fatigue Pages
Fatigue is From The Hypothalamus (Mainly)
All of the most important reasons have to do with the hypothalamus, which is something I discuss quite a bit.
Several hypothalamic areas, such as the suprachiasmatic nucleus (SCN), lateral hypothalamus (LH) and ventromedial hypothalamic nucleus (VMH) are implicated in the regulation of sleep, wakefulness and food intake (R).
NOTE: In the scientific literature, post-meal fatigue is known as “post-prandial fatigue“.
Post Meal Fatigue is a Metabolic Problem
Metabolism is the process where the energy goes in (caloric intake) and that energy is utilized by the body.
When energy isn’t utilized the way it’s supposed to, you’ll have a metabolic problem.
So for example, if you’re obese, the calories you take in are not being expended by having more physical and mental energy. Instead, it’s being stored as fat. That’s a metabolic problem.
Another metabolic problem is when you expend more calories than you take in and you get too thin. These calories might not be digested, they may be used for your immune system to create inflammation or you might have increased body temperature.
Being too thin or too overweight are both metabolic problems, just of a slightly different nature.
When you take calories in, it’s supposed to be used by your cells and make you feel more energetic, think better and have a better mood.
13 Reasons You Get Tired After Meals
1) Carbs and Glucose (by suppressing orexin)
Any carb will end up breaking down into glucose, so if you eat too much carbohydrates, you can feel tired after a meal.
When I eat too much carbs or glucose, I get tired. This used to be the case much more than it is now.
The reason why glucose used to affect me more has to do with changes in the hypothalamus. I’ve noticed that lectins (by causing inflammation) make me more sensitive to glucose-induced fatigue and since I restrict dietary lectins and other plant immunostimulants, this problem has minimized.
In general, carbohydrates and plant-based foods contain a diverse range of chemicals that are capable of spiking your immune system (i.e. causing inflammation), if you’re susceptible.
2) Inflammation (by suppressing orexin)
Many people have undiscovered food sensitivities and get inflammation from some component of their meals.
This was the most significant cause of fatigue after meals for me, and when I took out all of the foods that caused me inflammation, the post-meal fatigue went away.
3) Acidity, Orexin, and Post-Meal Fatigue
Orexin is extremely sensitive to the minor changes of pH in the blood.
When blood acidity temporarily goes down and your blood becomes slightly more alkaline, orexin will more likely to be suppressed and tiredness will ensue.
When you chew, your stomach needs to create hydrochloric acid (HCL), which is very acidic. This pulls some acidity out of your blood and temporarily causes a small increase in pH (lower acidity).
4) ATP and Orexin
Indeed, researchers have found that in CFS people have less pyruvate in their cells.
The mitochondria is what controls the production of energy-related molecules.
This means that if your mitochondria aren’t working well and you’re not producing adequate ATP, a meal with carbs will be more likely to make you tired.
Digestion is an energy intense process and I wouldn’t be surprised if it used a lot of ATP. Also, if you are getting inflammation from the food, that will deplete your energy reserves even more.
5) Leptin and Post-Meal Fatigue
Leptin is capable of spiking inflammation and making your tired. Leptin spikes are associated with fatigue in studies (R).
Interestingly, leptin increases more from carbohydrates than protein or fat (R), which may explain, in part, why carbs make people more tired than other macronutrients.
When you have an inflammatory environment, leptin is capable of causing much more inflammation, which is why fatigue will only occur from leptin if you already have inflammation.
Indeed, this is one reason why carbs make people feel more tired.
6) Low NAD+/SIRT1 and Post-Meal Fatigue
NAD+ also increases metabolism and acts as a signal for energy balance. When your mitochondria are working well, you produce more NAD+ and this sets in motion a bunch of signals to increase energy intake and expenditure.
NAD+ makes you more insulin and leptin sensitive. When you have low levels, your general energy will decline, your mitochondria will work less well, you’ll have higher blood sugar and this will increase the risk of post-meal fatigue.
7) Less Blood Flow to the Brain
When you eat, the blood vessels of the GI tract dilate, increasing local blood flow. Blood rushes to your stomach to start processing the food.
Since the blood is moving to your GI system, this means your brain has less blood and therefore less oxygen and nutrients. This can contribute to fatigue.
8) Parasympathetic Activation (rest and digest)
When you eat, your parasympathetic system (rest and digest) increases and the sympathetic system (fight or flight) decreases. This happens regardless of the composition of the meal (R).
Think about how you feel relaxed after a #2. That’s parasympathetic activation.
I experience this a bit after a meal, but it’s more of a relaxation than a fatigue – and to the extent that I do feel tired, it’s very mild and dissipates quickly.
Regardless, parasympathetic activation can contribute to post-meal fatigue.
9) Circadian Rhythms and Fatigue
You might notice that you feel more tired after lunch than breakfast or dinner.
This is because there’s a rhythm to wakefulness and at around 1-3PM, you naturally feel more tired. This is called the afternoon dip.
After 10AM, sleep urge starts to go up, peaking at about 2PM. The wavy orange/red line shows the circadian rhythm of fatigue. The other part (sleep need) illustrate the steady buildup of metabolic products such as adenosine that cause fatigue.
The bottom line is that you are more likely to get tired after lunch for circadian reasons.
10) CCK and Post-Meal Fatigue
Cholecystokinin (CCK) is a significant factor in post-meal fatigue.
CCK is a gut hormone that’s mainly released in response to a fat-rich or lectin-rich meal (R). Long chain fats (saturated, MUFAs, PUFAs) are especially potent CCK inducers (R). A high protein diet also increases CCK (R).
CCK also has stimulating properties by activating orexin. CCK receptors are in parts of the hypothalamus that stimulate wakefulness and fatigue. Giving a CCK blocker to rats prevented post-meal fatigue, whereas in humans it actually increased post-meal fatigue (R).
So it’s accepted that CCK has sleep-promoting and wake-promoting properties, but the balance will depend on other factors, in my opinion. If your hypothalamus is working well, it may be more wakeful promoting and if not, it can be more sleep promoting.
CCK directly interacts with the hypothalamus to stimulate the flow of your colon, which will cause gas (R).
CCK release almost certainly also follows a circadian rhythm and is likely released more in the day time when our system is primed to eat.
11) Insulin, BCAAs, and Tryptophan
The theory is that this lowers the ratio of these BCAAs in the bloodstream relative to tryptophan (R).
Uptake of tryptophan by the brain thus increases. In the brain, tryptophan is converted to serotonin, which is then converted to melatonin. Increased brain serotonin and melatonin levels result in sleepiness (R).
This might be why eating a higher protein meal can blunt the fatigue a bit.
12) Insulin-Induced Low Potassium
This can lead to a lower potassium state. The effects of low potassium include fatigue, muscle weakness, or paralysis (R).
However, when I supplement with potassium, it has perhaps a very small effect. This is certainly not very significant for me.
13) Cannabinoids and Orexin
Cannabinoids get their name from cannabis, or marijuana.
Cannabis is more often associated with making you sleepier, but in actuality, low levels of cannabinoids potentiate orexin and can stimulate wakefulness.
I’ve noticed that post-meal fatigue is more common when people have variations in their cannabinoid receptors. That could have to do with cannabinoids activating orexin or it could have to do with people with these variations being more sensitive to foods and therefore they have more inflammation from their diet.
Top Ways to Prevent Post-Meal Fatigue
Some of the most significant changes that have helped get rid of my post-meal fatigue was reducing plant-based foods in my diet (grains, beans, nuts, seeds), consuming less carbs and increasing my protein intake. See the lectin avoidance diet.
With SelfDecode, people can get a closer look of their genetics, which can help home in on the root cause of their fatigue.
Here are some of the best methods to help post-meal fatigue. These recommendations are a product of an insane amount of research and experimentation.
- Eat more protein with meals
- Avoid lectins
- Reduce carbs (to reduce leptin and insulin spikes)
- Get Sun on most of your body. Sun improves metabolism, mitochondrial function and blood flow. It also stimulates the dopamine system, which helps with wakefulness.
- Using an ICES device on your head and gut. ICES increases oxygen utilization.
- Drink Apple Cider Vinegar with meals – to increase metabolism, acidity, NAD+ and lower blood sugar
- Drink Kombucha with meals (for lactate, to prevent orexin suppression)
- Take Fish oil/DHA -to reduce inflammation and improve mitochondrial function
- Nicotine – to increase metabolism, NAD+, and orexin.
- Forskolin (95%) – increases mitochondrial function.
- Infrared Sauna – activates the nervous system
- Inositol before a meal (to reduce inflammation, insulin resistance)
- Curcumin a half hour before meal (to reduce inflammation)
- Butyrate a half hour before meal -will notice the benefits the day after
- Black Cumin Seed Oil with meal (to reduce inflammation)
- Andrographis – to reduce inflammation
- Caprylic acid – to increase energy production (ketones)
SelfDecode and SelfHacked Fatigue Pages
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