Eating While Stressed? This Is What Happens in Your Body.

by | March 3, 2020 | Articles, Stress Reduction

Imagine our ancestors, hunting or foraging for food, when they come upon a large predator with sharp teeth and big claws. They have a split second to decide, do they fight, or do they run? This natural instinct to survive is called the “fight-or-flight response.”

Our bodies are designed to help us stay alive in high-stress situations. Blood rushes to the muscles to increase power, adrenaline shoots up to sharpen the mind and our ability to focus, the adrenal glands produce the stress hormone cortisol to increase sugar in the bloodstream. All of these changes support optimal physical performance in a short-term effort to survive. Fight-or-flight is an amazing physiological response that keeps us safe in dangerous situations.

Now imagine yourself in present day. You are about to sit down for lunch at the office when your boss suddenly enters and starts yelling at you. He or she might not be as scary as a bear or a tiger, but in your body, the same fight-or-flight sympathetic nervous system response is triggered. Now you are eating your lunch completely stressed out and then you wonder what could have triggered your indigestion or other digestive issues.

Why Are We So Stressed?

woman on phone during meal

Although our lifestyles have changed quite a bit since the days of our ancestors, our basic wiring has not. In modern life, we experience stressors that are not life threatening yet they still trigger our sympathetic nervous system’s fight-or-flight response.

Today, stress has many shapes and forms. Our stress response can be caused by stressful events such as emotional or physical trauma. More often, however, it is the usual daily activities that can lead to chronic stress in most people.

You may have an extremely busy schedule, are often sleep deprived, or don’t regularly engage in relaxing activities you enjoy. With our busy lives, we rarely find the time to pause and just be. We hardly ever stop to appreciate the moment. Over time, these lifestyle choices can all contribute to chronic stress. The problem is that in many cases, we are not aware of how devastating these small habits can be to our health.

How Stress Affects Your Digestion

We now have enough data to know that stress is intimately connected to our entire physiology. We are beginning to understand how it affects all the different systems in the body, including our digestion.

When we are stressed, our body is getting ready for fight-or-flight, not to digest food; blood flow is diverted away from the gut into the muscles, the stomach’s pH level changes, and, with chronic stress, the gut microbiome is altered.[1,2,3]

I often see individuals who are going through transitions, or are undergoing particularly stressful periods in their lives, who travel frequently for work or do shift work. They often report gastrointestinal problems such as irregular bowel movements, bloating and stomach discomfort. When on vacation or after their stressful situation has resolved, however, these individuals’ symptoms can dramatically improve.

When we eat while we are stressed, our digestive system is not optimally digesting the food we eat. Our gut motility changes, and the body’s ability to absorb nutrients from food is impaired. During periods of stress, you also may notice digestive issues, even if you eat a healthy diet.

A Deeper Look at the Gut-Stress Connection

The gut-brain axis

There is a bidirectional relationship between the gut and the brain. This relationship is known as the gut-brain axis and consists of communication between central and enteric nervous system. It is a system that links the emotional and cognitive centers of the brain with the peripheral intestinal functions. While the brain has 100 billion neurons, our digestive tract has 100 million neurons. The neurons of our gut are connected to the neurons of our brain.

Brain regulates the gut via the EMS (emotional motor system), which consists of parasympathetic and sympathetic branches of the autonomic nervous system, the hypothalamic pituitary adrenal axis, and pain modulation systems.[4]

The vagus nerve

The vagus nerve is a well-studied nerve that connects our digestive system to our brain. It has fibers that sense information in the gut and deliver it to the brain. This information relates to food, toxins, the gut microbiome, inflammation, or infections.

Ninety percent of the vagus nerve fibers transport messages from the gut to the brain. The remaining ten percent of the vagus nerve fibers take information from the brain back to the digestive tract. The vagus nerve also plays a role in appetite, gut motility, and inflammation.

For instance, a study in humans found that individuals with irritable bowel syndrome and Crohn’s disease have reduced function of the vagus nerve. Vagus nerve stimulation is being studied as a potential therapeutic modality for inflammatory bowel disease.[5]

If we maintain a strong vagal tone, we are more relaxed. This is the state we want to be in when we are eating! Easy, natural ways in which we can stimulate the vagus nerve include deep breathing, gargling and humming.

The gut microbiota

We are also learning more about the impact of stress on the gut bacteria. But first, why are gut bacteria important?

The large intestine can contain up to 500 different species of bacteria, and the number of all microorganisms in our gut outnumber our own cells by a ratio of 10:1.

Here are some of the important roles that gut bacterial play for our health:


  1. Synthesize vitamins that are essential for our health, such as vitamin K and some B vitamins.
  2. Ferment non-digestible carbohydrates to produce short chain fatty acids such as butyrate, a major source of energy for enterocytes or cells of our intestinal lining. These short chain fatty acids are also known to reduce appetite.


  1. Anti-inflammatory properties
  2. Modulate our gut mucosal immunity and overall immune system (e.g., cytokines can be upregulated by certain gut bacteria, increasing inflammation)
  3. Protect intestinal cells from toxins
  4. Break down carcinogens in our diet


  1. Protect the intestine from colonization by other microbes or invasion by pathogens


  1. Stimulate neurotransmitter production.
  2. Associated with our stress response.

On the other hand, some species of intestinal bacteria (e.g., members of genus Bacteroides) can play a role in the development of inflammatory bowel conditions, such as Crohn’s disease or Ulcerative Colitis.[6,7,8]

Disturbance in the gut microbiota balance, known as dysbiosis, is associated with anxiety, depression, autism and functional gastrointestinal disorders, such as Irritable Bowel Syndrome.

Gut microbiota of individuals have been reported to change in response to military training in harsh conditions, and in association with psychological stress in mouse models as well as in humans.[9]

Conversely, when Lactobacillus probiotic was administered in a randomized control trial, it reduced anxiety in the subjects.[10]

More research is needed to better understand the stress-microbiome relationship, but we do know that practicing effective strategies to cope with stress is key for our health.

Common Problematic Eating Habits Caused by Stress

couple sitting on floor eating

I see more and more people eating while they are performing other tasks and completely distracted. For instance, we often eat while we are checking emails, talking on the phone, or watching the news. Isn’t multi-tasking the best way to be more productive? Eating doesn’t require much focus, right?

While being productive is often praised in our society, eating while doing other activities may not be appreciated by our digestive system, as we aren’t focused on the action of eating.

The process of digestion – why it is important to eat mindfully and chew your food!

The process of digestion begins in our mouth. Mechanical digestion, which refers to mechanically breaking down food through chewing, as well as chemical digestion, which refers to enzymes breaking down food, both start here. In the mouth, an enzyme, salivary amylase, produced by salivary glands, breaks down starches (e.g., breads, grains, rice), converting them into smaller carbohydrates.

Now, imagine eating on the go. Digestion cannot properly take place if eating quickly and swallowing food before chewing it properly. There is not enough time to allow amylase to do its job.

Once the food leaves the mouth, after being partially digested, the food forms a mass called a bolus. This bolus then travels down the esophagus into the stomach. It is important that gastric juice, which contains hydrochloric acid, and a protein digesting enzyme called pepsin, is acidic enough.

Pepsin acts optimally at a pH of 2, and its action deteriorates at a higher pH. Therefore, it is important to note that medications that lower the stomach acid, may reduce efficacy of pepsin, and thereby impact the digestion of protein. In addition to the action of pepsin, muscles of the stomach churn the food. The food mixture, along with gastric juice, is called chyme.

Next, chyme enters the first portion of the small intestine, called duodenum. There, it is exposed to pancreatic enzymes that break down fats, protein and carbohydrates. Bile, which is made by the liver, and stored by the gallbladder, is also released into the duodenum, to help digest fats.

Approximately 90% of nutrients are absorbed in the small intestine (with 10% absorbed in the stomach and the colon). Water and minerals are reabsorbed into the colon. Bacteria in the colon produce vitamins, including vitamin K, vitamin B12, thiamin and riboflavin, which are also absorbed into the blood, in the colon. Waste is eliminated through rectum and anus.

Eating mindlessly or too quickly leads to overeating. We often don’t realize we’re full because it takes time for the fullness signal to travel from the stomach to the brain. Since we are doing other activities in addition to eating, we never hear the signal, we just keep eating until the food is gone. Mindless eating not only leads to overeating, it also deprives us from the enjoyment of eating food.

The Plot Thickens: Gut Health Issues Triggered by Stress

girl pouring cereal in mouth

The connection between chronic stress and certain digestive conditions such as IBS (Irritable Bowel Syndrome), SIBO (Small Intestinal Bacterial Overgrowth) and intestinal permeability (leaky gut) has been documented, although it is still often overlooked.

It may start with occasional digestive symptoms such as gas, bloating, and constipation, but as these are so common, they are not always taken seriously. Eventually, many people end up with gastrointestinal symptoms that overtime become debilitating and affect our ability to socialize, go out to restaurants, or even work, due to the fear of stomach discomfort, gas or diarrhea. This may cause many individuals to severely restrict their diets, which is not a healthy solution for the long term.

Becoming aware of chronic stress as a risk factor, recognizing the early warning signs, and taking the right action is key.

While you may be able to address occasional digestive issues by paying more attention to your stress levels, eating a healthy diet, and watching your eating habits, it is always best to consult a qualified health care professional. This is especially important if you have digestive issues on an ongoing basis, are unsure what is causing the symptoms, or find yourself dealing with chronic stress.

Working with your doctor is essential. For example, a major part of the treatment for SIBO, IBS and leaky gut includes specific elimination diets, such as a low FODMAPs diet, that can be restrictive and not easy to follow. Elimination diets often have a trial and error component, where the diet has to be tailored to each individual to address her or his particular food sensitivities.

Before going through such a process, it is critical to properly diagnose the condition you have. Then, together with your qualified health provider, you can develop a customized plan based on your body’s unique needs, your preferences and other factors.

On that note, here are some of the digestive symptoms that require medical attention and further work up:

  • Blood in stool or black stool
  • Iron deficiency anemia in an individual at risk of gastrointestinal bleeding (this may be occult bleeding, therefore not something that an individual would notice)
  • Fatigue, lack of exercise tolerance or dizziness
  • Nausea and/or vomiting
  • Abdominal pain
  • Unintended weight loss
  • Chronic or severe diarrhea
  • New onset constipation that has not been worked up in the medical setting
  • Severe or constant abdominal pain (any part of the abdomen)
  • Abdominal symptoms accompanied by fever.

My Top Tips to Manage Stress Before Eating

healthy meal on table

Now that you have an understanding on the connection between stress and gut health, what can you do about it when you are in a stressful moment?

You are at work, it’s lunch time, but things are crazy in the office. Tension is high, deadlines are approaching, but you have to eat sometime, right? How can you mitigate the impact of stress to prevent it from impacting your digestion?

Mindful Eating

Mindfulness-based stress reduction and mindful eating are excellent tools to promote healthy eating habits.

Mindful eating is an approach to food that focuses on your awareness and experience of the food you eat. It involves slowing down and experiencing the meal with all of your senses. This requires taking the time to connect with the food you have in front of you.

What does it look like? What does is smell like? What is the texture when you put it in your mouth? Experiencing eating as a sensory activity is how you become mindful while you are eating. You may notice how enjoyable it is to eat certain foods, but on the other hand, you may also recognize some discomfort during or after eating others.

I have personally found mindful eating very helpful in setting up healthy behaviors around eating. A literature review showed that mindfulness-based interventions can reduce binge and emotional eating and improve overall eating behaviors.[11]

Tap into Natural Hunger Signals

Mindful eating can also help you learn how soon you get satiated and full after you eat. Only start a meal if you are feeling hungry, but also don’t wait until you are starving to eat, or you will end up overeating.

Once you start eating, pay attention to the signals your body is sending you. Instead of waiting until you feel 100% full, try to stop eating when you’re about ⅔ of the way and see how you feel. This may help you limit portions and avoid overeating. Your body knows exactly how much it needs, if you just slow down enough to listen.

Minimize Distractions While Eating

Rather than having lunch at your desk and working while you eat, plan to sit with a co-worker and have a pleasant and meaningful conversation. Or find a peaceful location to enjoy lunch where there will be less distraction while you are eating.

Break the Habit of Having That Extra Snack

When you work in an office, it often seems that somebody always brings candy, muffins, potato chips and other processed food to share. Frequently we eat these snacks because they are available, not because we are actually hungry. Before grabbing a snack, ask yourself if you are really hungry or are eating because food is there and you may be bored.

If you are hungry, junk food likely won’t satisfy true hunger. Instead, always have healthy snacks on-hand so that when you’re hungry, you don’t just grab the closest, unhealthy food within reach. Nuts, fresh fruit, carrots and hummus are all healthy options you can easily take with you to work.

Listen to Your Body

Our body sends us signals for a reason. We can get a lot of valuable information if we listen and act on these signs, especially when it comes to digestive issues that are so often overlooked. Be mindful of any warning signs and share them with a qualified health provider who can help you get to the root cause of your symptoms, work up any worrisome symptoms and help you focus on lifestyle and nutrition approaches to address the root cause.

Stress Management Activities

Stress Management Activities Chronic stress is one of the most serious health challenges of our time. Multiple studies have clearly identified stress as a major risk factor for multiple chronic diseases.[12]

Humans are naturally programmed to seek security and control; with the fast pace and unpredictable nature of modern life, it can be very hard for us not to worry about things that are beyond our control. Stress can take over our lives, if we let it.

Luckily, we have also developed many activities and techniques that can be exceptionally helpful in managing and relieving stress, if we implement them. More on this in our upcoming article!


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