Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.
Your gut is no longer a mystery. We’ve learned that your gut is in charge of some incredibly important tasks, from weight loss to immunity to sound sleep. And we’re paying closer attention to gut health, carefully curating colonies of beneficial bacteria. But in taking care of your gut, you have to keep your diet – and your hunger levels – in mind.
Your gut is where food goes to get digested, after all. And the digestion process is proving more important than previously known. New research shows that the foods and nutrients you eat can alter the signals your gut sends to your brain. This has the potential to impact everything from how much you eat to how your brain and gut communicate.
Your gut’s nerve cells tell your brain when you’re hungry
A research study published in May 2021 and conducted by researchers in Cologne, Germany set out to examine the communication between the gut and the brain. Scientists already knew that the gut and brain “speak” to one another via the vagus nerve, one of the body’s most critical nerves. This nerve can be stimulated by the gut and vice versa, shaping both brain and gut activity.
But the study’s researchers didn’t simply examine the vagus nerve; they looked at the different cells within the nerve’s “control center” and how they function. When you eat, certain nerve cells are activated and start sending signals from your gut to your brain along the vagus nerve. Your gut shares information about what you’ve eaten, and your brain takes that information and decides whether you should keep eating or stop.
All of the nerve cells handle different jobs and signals. Some, for example, determine whether or not your stomach needs to stretch while you’re eating. Others are responsible for figuring out what nutrients you’ve consumed. And some take charge of what’s happening in your intestines.
Ultimately, when the nerve cells transmit all of this information from your gut and send certain signals to your brain, it can either spark or shut off your hunger. Some foods might lead your brain to tell you to keep eating; others may make you “feel” full quickly. Though you might literally feel full and ready to stop eating, you don’t have much say in the matter. It’s all about what signals your gut is sending and how your brain reads them.
Different nerve cells can be activated with different foods
The breakthrough finding of the latest study was the discovery that a couple particular types of nerve cells are responsible for shaping your hunger.
Researchers spent time turning specific nerve cells on and off, analyzing each cell type’s specific function and signals. They were able to manipulate the cells’ responses, and they pinpointed which cells supplied particular organs and which signals they picked up from the gut.
And they saw that two types of nerve cells in the nodose ganglion (a small, sensory area of the vagus nerve) were causing the mice involved in the study to eat less. One kind of cell, called GLP1R, detected stomach stretching; when these nerve cells became active, they reduced appetite. The GLP1R nerve cells told the brain that it was time to stop any further food intake, and they also coordinated blood sugar control.
The other cells, called GPR65, had something of an opposite effect. These nerve cells activated the intestine’s nerve cells, spurred an increase in blood sugar and had no regulating effect on appetite. With these cells in play, the brain didn’t get the signal to stop eating – and appetite wasn’t really satiated.
Researchers deduced that foods with a lot of volume, enough volume to stretch the stomach, are able to activate the nerve cells that tell your brain to shut down your appetite. However, nutrient-dense foods activate the other nerve cells, which means your brain doesn’t get any signals about your food intake level.
Can you control your gut’s hunger signals?
While there isn’t much you can do about these gut-to-brain connections and signals, you can keep the study’s findings in mind.
While huge portion sizes or large amounts of high-volume foods might make you feel full faster, eating smaller yet nutritionally-dense foods may send signs that you should keep eating. It’s a good idea to keep the size of your meals and servings in mind – your gut might not tell you you’re full when you’ve had enough!
Additionally, now that you know that your gut is directly communicating with your brain, you can also put new habits into practice so you can really tell when you’re full. Take your time to eat slowly and intuitively. It can take time for your brain to receive and translate the gut’s messages. If you’re switching to a more nutrient-dense diet, it’ll take time for your body to adjust as you limit carb-heavy foods. You might feel ravenous initially, but as you see more stable blood sugar, you’ll likely find those hunger pangs wane.
Your gut can shape your hunger and satiety levels, along with many other facets of your health and wellness. To learn more, keep reading: