The Vagus Nerve and Weight Loss

What is the vagus nerve, and why is it so important?

The vagus nerve, also known as cranial nerve 10, is the information superhighway that signals from your brain to your organs and back again. It’s part of the autonomic nervous system - the branch of your neurology that works outside of your conscious control to maintain things like digestion, circulation, respiration, and many other life-sustaining functions.

The vagus nerve acts as a thermostat for organ regulation - like I mentioned, it doesn’t only send information down from the brain to your organs.

It also has fibers that send information from your organs back to your brain - and this is a very big deal, Because it allows the vagus nerve to both command and control digestive function, immune function, inflammation, blood pressure, hormone regulation, and much more.

Its objective is homeostasis - or steady-state - which is why we talk about it a lot in the context of stress, because the vagus nerve helps balance your sympathetic and parasympathetic nervous systems.

The sympathetic nervous system or SNS is your fight/flight/freeze response to stress while your parasympathetic nervous system or PNS is in charge of rest, digestion, and recovery.

In a world full of stressors, the responsivity and balance of these systems is crucial for mental, emotional, and physical well-being.

If your vagus nerve is not able to communicate effectively or efficiently, we sometimes refer to this as poor vagal tone, and it can contribute to some serious problems.

I just can’t overstate how integral the vagus nerve is - especially when we’re taking a functional medicine approach - because it really ties everything together.

How would you know if you have poor vagal nerve tone, or if your vagus isn’t functioning properly?

Some symptoms include the following:

And, trouble achieving or maintaining a healthy body composition or weight can also be a symptom of the systemic impact of poor vagus nerve function.

We’ll dive into this specific situation in a minute!

Since so many of these symptoms overlap with other conditions, it can be helpful to get a measurement of your vagus nerve function - and one of the ways we can do that is by measuring heart rate variability.

Using a device that picks up your heart rhythm, HRV measures the milliseconds between your heartbeats and then compares them to each other. For instance, sometimes your heart might beat every 1.2 seconds, and at other times it might beat every 0.8 seconds.

This slight variation in timing is an indicator of how well your body can adapt to stress, and how gracefully your neurology can shift from sympathetic to parasympathetic - which can also be thought of as your body’s resilience.

More variability is better and is associated with lower cardiovascular risk, quicker recovery, and better vagus nerve function.

You’re probably wondering what all of this has to do with weight loss - so let me explain a few mechanisms by which improved vagal nerve function can decrease body fat.

First, if you have poor vagus nerve tone, you’re likely living most of your life in a sympathetic-dominant, fight-or-flight state.

When you get stuck in stress mode, over time your body releases more of a hormone called cortisol, which is linked to a host of chronic diseases including metabolic syndrome, fat gain, and weight-loss resistance.

Chronic cortisol overproduction can also trigger sex hormone imbalances, which are linked to poor body composition - especially for women. Improving the function of your vagus nerve is huge for creating stress resilience and has many other benefits besides body fat loss.

The second way your vagus nerve can help you lose weight is by regulating inflammation.

Decreased vagal tone can result in higher, more persistent systemic inflammation, which can lead to water retention and puffiness as well as blood-sugar imbalance and fat gain.

Third, the vagus nerve is a critical part of the GLP-1 signaling pathway, which helps regulate satiety.

GLP-1 or Glucagon-like peptide-1 is a compound that is made in your gut, or gastrointestinal tract, when you eat. GLP-1 communicates to the brain, via the vagus nerve, telling you when you’ve had enough to eat.

That’s how GLP-1 agonists like Ozempic and Mounjaro, as well as natural GLP-1 boosting agents like Berberine can help decrease appetite and food cravings.

GLP-1 also slows down how quickly food moves from your stomach to your intestines, a process called gastric emptying. This keeps you feeling “full” longer so you eat less, which can result in weight loss for some people.

So, even if you’re making plenty of GLP-1 and you have very sensitive receptors, you’re not getting the full weight-loss benefits without a toned vagus nerve!

The last (direct) way that the vagus nerve can help you achieve and maintain a healthy weight is by supporting a healthy microbiome in your gut.

Many keystone bacteria that help regulate metabolism and inflammation live in a mucous-rich layer right next to your intestinal cells.

One of these very helpful bugs is called Akkermansia muciniphila, and as it’s name implies, it needs a healthy mucous layer to thrive.

Well, the cells that make and support your intestinal mucous layer are called goblet cells, and they are regulated by acetylcholine that is released from the vagus nerve.

So, if you have poor vagal tone, resulting in a skimpy mucous layer, you might not have as many metabolism-boosting, inflammation quenching Akkermansia to help you out, which can lead to weight gain.

Now that you understand how toning and stimulating the vagus nerve can help you lose unwanted body fat, it’s time to talk strategy.

Here are some evidence-based action steps to optimizing your vagus nerve! And, just so you know, I’ve compiled these strategies and a few others into a free checklist for you to download - you can grab your copy HERE.

How you breathe has a huge impact on your vagus nerve, and on the balance of your autonomic nervous system in general.

When you inhale, your sympathetic nervous system, or fight/flight/freeze is dominant, and when you exhale, your parasympathetic nervous system becomes dominant.

So, given that most of us spend too much time in sympathetic activation, it’s helpful to practice breathing exercises that involve a higher ratio of exhalation to inhalation. I really like a 4-7-8 breathing pattern with the goal being to double your exhale.

It’s also important to work on breathing through your nose, as opposed to your mouth, and to inhale and exhale from your diaphragm instead of your shoulders or chest. I know breathwork can seem cliche or even a bit silly, but research shows that it’s the very best way to optimize vagus nerve function.

Because fibers of the vagus nerve provide communication from the vocal chords to the brain, we can literally use our voices to improve vagal tone.

Humming, singing, chanting, and even gargling can stimulate the vagus nerve and improve its function.

Humans have been performing these exercises, often communally, for millennia - but as we become more isolated, stressed, and reliant on technology to communicate, we may not find ourselves gathering to sing, “om,” or laugh as regularly.

That means it’s a good idea to make these strategies personal habits - by gargling every night with a big glass of water, humming a tune as you walk, and singing out loud to your favorite songs in the car.

The vagus nerve also needs nutritional support to function properly - and there are a few specific micronutrients and nutraceuticals that can boost fat loss both directly via the vagus nerve and indirectly.

B vitamins are needed for optimal neurologic signaling because the mitochondria or powerhouse of the cell requires B vitamins like B12 and folate to produce energy. When my one-on-one clients and I do micronutrient testing, it’s really common to find sub-optimal levels of B vitamins in their labs.

Choline is a micronutrient that is deficient in 90% of diets, and it is crucial for vagus nerve signaling. Eggs, especially eggs with a runny yolk, and organ meats are the most concentrated food-based sources of choline.

But it can also be helpful to supplement, especially if you’re not a big fan of liver and over-easy eggs.

Phosphatidylcholine is my preferred source of supplemental choline because of its high absorption and bioavailability - I’ll share my favorite phosphatidylcholine product in the free Vagus Nerve Optimizing Checklist.

Lastly, while it might not be a micronutrient, supplementing with Akkermansia muciniphila is a well-documented strategy for supporting healthy weight loss, and is directly related to the vagus nerve since poor vagal tone can cause a deficiency in this keystone, metabolism-regulating microbe.

If you’re struggling with weight loss and you don’t know what to do next, supporting your vagus nerve is a fantastic strategy to try! Be sure to sign up for your copy of the free Vagus Nerve Optimization Checklist - you can sign up HERE.