By Alice || Edited by Go Ask Alice Editorial Team || Last edited Apr 19, 2024
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Alice! Health Promotion. "Why do I get flushed and tired after eating lunch?." Go Ask Alice!, Columbia University, 19 Apr. 2024, https://goaskalice.columbia.edu/answered-questions/why-do-i-get-flushed-and-tired-after-eating-lunch. Accessed 24, May. 2024.

Alice! Health Promotion. (2024, April 19). Why do I get flushed and tired after eating lunch?. Go Ask Alice!, https://goaskalice.columbia.edu/answered-questions/why-do-i-get-flushed-and-tired-after-eating-lunch.

Dear Alice,

I find that when I eat lunch I can feel myself instantly get tired as if a wave passes through me. My face gets a feeling of being sweaty and flushed. Coffee and copious amounts of water help counteract this. Also, it doesn't happen every day with every meal. Very small amounts of food don't cause this. It's as if I eat above a small threshold, then it happens. It makes it hard to work. A short nap would be perfect (but not possible). Is this something to be worried about?

Dear Reader, 

It sounds like you’ve been succumbing to a food coma, or what’s medically known as Postprandial somnolence. While it’s hard to tell whether this happens because of your meals or another condition (more on this later), understanding potential causes can help prepare you for all outcomes if you decide to speak with a medical professional about it. Depending on the underlying reason for the post-meal fatigue, treatments could include medications, diet modifications, or behavioral changes. 

Postprandial somnolence can happen after any meal, not just lunch. It’s often characterized as feeling tired or fatigued after eating. Depending on what you ate, this sleepiness may be caused by foods high in fat, carbohydrates, tryptophan (an amino acid found in many proteins), or melatonin (a natural hormone found in nuts, such as walnuts and pistachios, as well as tart cherries, eggs, salmon, etc.). The timing of meals is critical as well. For instance, late meals can disrupt the circadian rhythm and contribute to fatigue. What you drink with a meal can also alter your energy levels. Alcohol consumption can contribute to tiredness and impact the quality of rest. Coffee and other caffeinated drinks might help you stay awake during the day but can also interfere with a good night’s sleep if consumed too late. On the other hand, water is important for hydration, and it helps you stay alert. Perhaps the types of foods you consume, the components of the meal, and your natural circadian rhythm are combining to form the symptoms you have described. 

Besides the food you eat, a “food coma” may also be caused by various underlying medical conditions. Some conditions that may contribute to fatigue following a meal include: 

  • Dumping syndrome: This condition refers to a set of symptoms that occur when the food you’ve consumed moves too rapidly from your stomach to the first section of your small intestine. This process is referred to as rapid gastric emptying. Dumping syndrome is common after gastric surgery, and is often associated with symptoms like nausea, cramps, flushing, and dizziness shortly after eating. It can also lead to sweating and weakness a few hours after consuming a meal with high sugar content. 
  • Diabetes: This is a common condition that’s related to compromised insulin production or inability to use insulin properly, which can lead to excess sugar levels in your body. Insulin is a hormone that regulates blood glucose levels. When the process of regulating glucose levels is compromised, this can lead to symptoms such as fatigue, thirst, hunger, and numbness. Compare this to reactive hypoglycemia, which occurs when a person has low blood sugar after eating. Some signs of reactive hypoglycemia can be weakness, sweating, and lightheadedness. 
  • Gustatory hyperhidrosis (sometimes referred to as Frey’s syndrome): This condition is associated with sweating during, or following, consumption of food. It can be connected to diabetes, thyroid problems, nervous system disorders, and other conditions. 

Whatever the reason, speaking with a medical professional may help pinpoint the true cause. They may recommend medications or prescribe a specific diet. 

Regardless of whether you’re diagnosed with one or none of these conditions, there are strategies that you can try to combat your post-lunch dip including: 

  • Eating smaller portions in conjunction with snacks throughout the day 
  • Decreasing the fat or carbohydrate content of meals 
  • Regulating circadian rhythms by improving sleep hygiene 
  • Exercising to increase energy 
  • Taking a short nap when possible 
  • Exposing yourself to bright lights as an alternative to a short nap 

The effectiveness of each strategy will depend on the person, but they all aim to target the factors that make people feel tired after eating. Best of luck in staying alert during your post-meal endeavors! 

Additional Relevant Topics:

Nutrition and Physical Activity
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