I admit, I’ve been pretty confused about all the advice out there about high-fat diets.

On one hand, low-carb, high-fat diets like paleo, keto and carnivore have been linked with weight loss and improved inflammation, cholesterol, blood sugar and insulin levels — not to mention a 20 percent reduction in glaucoma risk.

On the other, there is a proven link between a high-fat diet and several serious health threats.

Diets high in fat, particularly saturated and trans fats, also can lead to heart disease, metabolic syndrome and an unhealthy gut environment.

Now, there is another disorder to add to the “bad” side of high-fat dieting…

High-fat diet, leaky gut and anxiety

Researchers at the University of Colorado Boulder used an animal model to see the impact of a high-fat diet on the gut microbiome and behavior. Half the rats in the study were fed a standard diet of about 11 percent fat for nine weeks, while the others got a high-fat diet of 45 percent fat, consisting mostly of saturated fat from animal products. 

The typical American consumes a diet of about 36 percent fat, according to the Centers for Disease Control and Prevention.

After nine weeks, the group eating a high-fat diet gained weight, as expected, compared to the control group. The high-fat diet group also showed significantly less diverse gut bacteria and hosted far more Firmicutes bacteria and fewer Bacteroidetes bacteria. A higher ratio of Firmicutes to Bacteroidetes is associated with obesity.

These rats also showed higher expression of three specific genes (tph2, htr1a and slc6a4) involved in the production and signaling of serotonin, particularly in a region of the brainstem associated with stress and anxiety.

We usually think of serotonin as the “feel-good” brain chemical. However, when activated, certain subsets of serotonin neurons can prompt anxiety-like responses in animals, notes lead author Christopher Lowry, a professor at CU Boulder.

Notably, heightened expression of tph2 in the brainstem has been linked with mood disorders and suicide risk in humans.

In short, the study found a diet high in fat appears to influence brain chemicals in ways that trigger anxiety.

“To think that just a high-fat diet could alter expression of these genes in the brain is extraordinary,” Lowry says. “The high-fat group essentially had the molecular signature of a high anxiety state in their brain.”

According to Lowry, an unhealthy microbiome may compromise the gut lining. This can result in a condition known as leaky gut and may enable bacteria to enter the body’s circulation and communicate with the brain through the vagus nerve, a pathway from the gastrointestinal tract to the brain.

Get the “good” dietary fat

So, is fat good or bad for you? As Lowry stresses, it all depends on the type of fat. Healthy fats like those found in fish, olive oil, nuts and seeds — the essential omega-3 fatty acids — can be anti-inflammatory and good for the brain.

Lowry advises us to ditch pizza and fast food and eat as many different fruits and vegetables as possible. Ultra-processed foods are also sources of saturated fat. He recommends adding fermented foods for a healthier gut microbiome.

If you do indulge in the occasional burger, Lowry suggests adding a slice of avocado to it. Some research indicates “good” fat can counteract some of the “bad” fat, and avocado is loaded with healthy monounsaturated fats.

Also, you could take the antioxidant resveratrol to help counteract the effects of unhealthy fat, since it’s almost inescapable. According to previous research resveratrol can correct the harmful effects of a high-fat diet on the brain and may be a potential therapeutic agent against obesity-related disorders.

Editor’s Note: You’re invited to join a tiny handful of Americans who enjoy rare, fresh-pressed olive oil all year long. Take my word for it, there’s a difference in taste, quality and benefit! Click here to learn more…

Sources:

Study shows a high-fat diet may fuel anxiety — EurekAlert!

High-fat diet, microbiome-gut-brain axis signaling, and anxiety-like behavior in male rats — Biological Research