The Nerve That Stops You From Losing Weight and Upsets Your Stomach

Robin Berzin, MD
March 20, 2016

Ever wonder why you have butterflies in your belly when you’re nervous, why your digestion speeds up or slows down when you are under stress, or why some people faint at the sight of blood?

The reason for these common experiences is the delicate connection between our bodies and our brains.

We usually think of our brains as separate from our bodies. In fact, most people are living as if there is a concrete wall blocking one from the other. But the reality is that our brains and bodies are intimately and intricately connected. And the vagus nerve is one of the most important ways they are tied together.

Keep reading to learn all about one of the most important nerves you probably didn’t even know you had and 5 ways to help you stimulate this super nerve to optimize its functioning and your overall health.

What is the vagus nerve?

The vagus nerve is also known as Cranial Nerve 10, and you actually have two of them – a pair, right and left, which extend from both sides of the brainstem down through the neck, innervating the heart, lungs, esophagus, and digestive tract.

The Vagus nerve, also called “The Wanderer” in Ayurveda, which is traditional Indian medicine, is part of the autonomic (think “automatic”) side of your nervous system. That means you don’t control this nerve the way you do your motor nerves – the vagus signals your digestion to move without you having to think about it, unlike for example when you choose you reach out your arm and pick up a cup of coffee.

Most importantly the vagus controls your relaxation response. It is part of the “parasympathetic” side of your nervous system, which is the “rest, relax, digest and heal” side. This is the counterpart to the “sympathetic” nervous system, which is the “fight or flight” side of the autonomic nervous system.

What is the purpose of the vagus nerve? Why is it important?

Because the mind and body are so deeply connected, at Parsley Health we don’t view them as separate. That’s why we ask about your stress levels, old trauma, anxiety and mood, and ask how your relationships are doing as we know that the other people in your life (from friends to bosses to partners) are probably determining how what you eat, how much you exercise and how stressed you are more than any other factor.

From what I see every day, most people are living their lives in a state of permanent fight or flight due to chronic stress, meaning that as far as their body is concerned they might as well be running from a lion from the moment they wake up to the moment they go to sleep .

Their sympathetic nervous system – fight or flight – is in overdrive and their vagus nerves are basically asleep.

Sound familiar? If so, you could be sabotaging your digestion and your weight loss goals at the same time. And the key to getting past these two connected hurdles isn’t just about food and exercise. It’s about breaking through that concrete wall and getting into your head.

Three common problems that all stem back to the vagus nerve.

1. Gas, bloating, constipation, and IBS

If your belly is a wreck , your brain may be to blame. The vagus is responsible for moving food through the esophagus stomach and small intestine, as well as the production of essential acids from the stomach and digestive juices from the pancreas. Dysregulated vagal activity has been associated with problems with motility, and the digestion and absorption of food, leading to the overgrowth of bacteria in the digestive tract, and thereby increasing bloating and constipation.

2. Overeating

The vagus is responsible for triggering your sensation of fullness, or satiety via a hormone called leptin which is released in the gut as part of digestion and stimulates the vagus. The opposite of leptin, a hormone called ghrelin, stimulates appetite by turning off the vagus nerve.

3. Inflammation

Multiple studies have shown that people with higher vagus nerve activity have lower levels of cortisol , the stress hormone, and lower levels of TNF-alpha the inflammatory immune marker. Studies also show that the vagus nerve regulates inflammation throughout the body, including inflammation associated with obesity, and could be a key modifier of obesity .

How do you stimulate the vagus nerve to work?

Stimulating the vagus nerve has been shown to improve conditions including:

So what is the top way to stimulate the vagus nerve? It’s easy. Relax. Or maybe that’s not so easy. If finding moments of true relaxation in your life are hard to come by, that could be the key factor that is driving your digestive issues and weight gain. I’d say you need to break through that concrete wall. Consider the following approaches:


Meditation can increase the positive emotions you experience and the social connection you feel with those around you. The influx of positive emotions increases your vagal activity, which transitions you into “rest and digest” mode, helping to alleviate symptoms of both anxiety and depression.

Deep Breathing

A simple breathing exercise in which you’re breathing through your belly rather than your chest has been shown to stimulate the vagus nerve. Belly breathing, like this box breath exercise , allows you to interrupt your stress response system and bring down your heart rate and blood pressure .


The mind-gut connection is more than just a saying, but an actual communication channel . It’s through the autonomic nervous system, where the vagus nerve lies, that the brain and gut send signals to one another. Probiotics may positively impact your vagus nerve by reducing inflammation in the gut microbiota. Certain strains of probiotics have shown to increase GABA , the relaxation neurotransmitter in the brain, via stimulation of the vagus nerve.


In general, yoga increases your vagus nerve activity and parasympathetic system. Yoga breathing directly stimulates the vagus nerve and improves your autonomic regulation, which is your ability to react to environmental cues without thinking. This form of breathing can also your improve cognitive function and mood. Studies have shown that yoga increases your GABA levels as well. High levels have been seen to improve mood and decrease anxiety.

Robin Berzin, MD

Dr. Robin Berzin is the Founder and CEO of Parsley Health, America's leading holistic medical practice designed to help women overcome chronic conditions. She founded Parsley to address the rising tide of chronic disease in America through personalized holistic medicine that puts food, lifestyle, and proactive diagnostic testing on the prescription pad next to medications. Since founding Parsley in 2016, Dr. Berzin has seen 80% of patients improve or resolve their chronic conditions within their first year of care, demonstrating the life-changing value of making modern holistic medicine accessible to everyone, anywhere. Parsley is available online nationwide.

Dr. Berzin attended medical school at Columbia University and trained in Internal Medicine at Mount Sinai Hospital in New York City. Her book, Prescription for Happiness: How to Eat, Move, and Supplement for Peak Mental Health, was published by Simon Element in January 2022.

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