Avoid reaching for a hamburger and fries when you’re stressed. While it’s natural to crave unhealthy food when stressed, scientists have found that instead of providing comfort, it can harm your mental health by increasing anxiety.
Previous research has shown that switching from a high-fat, high-sugar, ultra-processed diet to a healthier diet can reduce the risk of depression and anxiety overall.
In recent test published in the journal Biological Research, researchers examined the underlying factors underlying the link between a high-fat diet and anxiety. They found that a high-fat diet destroyed gut bacteria in animals, leading to changes in behavior and affecting brain chemicals through a complicated gut-brain connection. This disruption ultimately contributes to increased anxiety.
An earlier study by the same researchers found that when rats were fed a diet high in saturated fat, they showed increased levels of neuroinflammation and behaviors indicative of anxiety.
“Everyone knows it’s not a well food, but we tend to think of it only in terms of minor weight gain. If you understand that they also affect your brain in ways that can cause anxiety, then the stakes are even higher,” said lead author Christopher Lowry in: Press Release.
During the nine-week study, the rats were divided into two groups. One group received a standard diet containing approximately 11% fat, while the other group received a high-fat diet containing 45% fat, consisting mainly of saturated fat from animal products.
According to the Centers for Disease Control and Prevention, the typical American diet consists of 36% fat.
Throughout the study, researchers collected stool samples and examined the rats’ gut bacteria. At the end of the study, the team conducted behavioral tests on the animals.
As expected, rats on the high-fat diet gained more weight compared to rats on the standard diet. The researchers noted that there was less diversity of gut bacteria, indicating poorer health. There was also an escalate in bacteria called Firmicutes and a decrease in bacteria called Bacteroidetes. A higher ratio of Firmicutes to Bacteroidetes is associated with a typical industrial diet and obesity.
“The high-fat diet group also showed higher expression of three genes (tph2, htr1a and slc6a4) involved in the production and signaling of the neurotransmitter serotonin – particularly in an area of the brainstem called cDRD, the dorsal raphe nucleus, which is associated with stress and anxiety,” we read in the press release.
Although serotonin is often called the “feel-good brain chemical,” there are subsets of serotonin neurons that trigger anxiety-like responses in animals when activated, Lowry explained.
“To think that a high-fat diet alone could change the expression of these genes in the brain is extraordinary. The high-fat group essentially had the molecular signature of a high-anxiety state in the brain,” Lowry added.