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In the 1990s, researchers from the department of psychology at Yale University discovered that the “stress hormone” cortisol triggers excessive abdominal fat deposits in both men and women. These findings showed, for the first time, that the secretion of cortisol was associated with both chronic stress and an increase of abdominal “belly fat.” Stress has long been known to trigger the desire to eat more, which exacerbates weight gain by increasing caloric intake.
A new study has identified another chain reaction triggered by chronic stress that slows fat metabolism and makes it difficult to lose weight. Researchers from the University of Florida (UF) recently discovered that chronic stress stimulates the production of a peptide hormone called betatrophin, which inhibits an enzyme required for fat metabolism.
Chronic Stress Produces Betatrophin, Which Slows Fat Metabolism
The January 2016 study, “Angiopoietin-Like Protein 8 (Betatrophin) Is a Stress-Response Protein That Down-Regulates Expression of Adipocyte Triglyceride Lipase,” was published in the journal Molecular and Cell Biology of Lipids.
In 2013, betatrophin made headlines when researchers at the Harvard Stem Cell Institute (HSCI) reported that the hormone could increase the number of insulin-producing beta cells in people with diabetes. Unfortunately, later research found that betatrophin doesn’t actually improve beta cell production.
Now, betatrophin is back in the spotlight. According to Li-Jun Yang, a professor and lead investigator in the UF College of Medicine's department of pathology, immunology and laboratory medicine, betatrophin is a stress-related protein that makes it difficult to break down body fat and lose weight. While these findings have yet to be tested in a clinical setting, Yang believes the discovery has potential implications for humans.
For the recent study, experiments on cells derived from both mice and humans were used to establish betatrophin's role in body fat regulation. Then, the researchers studied how betatrophin levels increased as mice experienced environmental and metabolic stress. Both types of stress boosted betatrophin production in fat tissue and the liver. These findings establish betatrophin is a stress-related protein.
The mice who experienced metabolic stress produced significantly more betatrophin, and their normal fat-burning processes slowed down significantly. These discoveries are important because they shed new light on the intertwined biological mechanisms that link stress, betatrophin, and fat metabolism.
While researchers have yet to verify betatrophin's effect on fat metabolism in humans, Yang believes that these new findings explain why making an effort to reduce long-term chronic stress can also facilitate weight loss. Yang concludes, "Stress causes you to accumulate more fat, or at least slows down fat metabolism. This is yet another reason why it's best to resolve stressful situations and to pursue a balanced life."
Body Fat Sends Signals to the Brain That Can Trigger Stress
Last year, a team of researchers discovered that body fat can send signals that affect how the brain handles both stress and metabolism. The feedback loop between body fat and stress is a two-way street that can create a vicious cycle.
The July 2015 study, “Adipocyte Glucocorticoid Receptors Mediate Fat-to-Brain Signaling,” was published in the journal Psychoneuroendocrinology.
The exact mechanism of these signals remains enigmatic, but the researchers believe that having an awareness of the “fat-to-brain” feedback loop is a critical first step for breaking this vicious cycle.
In a press release, James Herman, a co-author of the paper and a professor in the department of psychiatry and behavioral neuroscience at the University of Cincinnati, said,
“Stress causes a desire to eat more, which can lead to obesity. And too much extra fat can impair the body's ability to send a signal to the brain to shut off the stress response. The findings are important and unique because they show that it's not simply the brain that drives the way the body responds to stress.
It moved our understanding of stress control to include other parts of the body. Before this, everyone thought that the regulation of stress was mainly due to the brain. It's not just in the brain. This study suggests that stress regulation occurs on a much larger scale, including body systems controlling metabolism, such as fat."
The researchers found that a glucocorticoid receptor in fat tissue affects the way the brain controls both stress and metabolism. Initially, such signals from the receptor can be lifesavers, directing the brain to regulate its energy balance and influencing stress responses in a beneficial way. However, over the long-term, this can backfire.
Apparently, hormones known as glucocorticoids activate receptors within fat tissue in a way that triggers a metabolic stress response. In an experiment using mice, the researchers found a unique connection between glucocorticoid signaling in fat tissue and the brain's regulation of energy balance and stress response. Understanding fat-to-brain signaling is a first step toward someday being able to influence the broad, complex relationship between stress, obesity, and fat metabolism.
Now that researchers have established that a fat-to-brain signaling pathway exists, a better understanding of how it functions might someday lead to drugs or other therapies that minimize the negative effects of long-term stress and excess body fat.
Conclusion: Dual-Pronged Approach to Reduce Both Body Fat and Stress
There appears to be a triple whammy in play that makes it difficult for people who are chronically stressed to lose weight. First, stress creates the desire to eat more. Second, stress triggers the release of hormones such as cortisol and betatrophin that increase abdominal fat and slow metabolism respectively. Third, fat-to-brain signaling appears to increase stress levels as part of a feedback loop that entrenches this vicious cycle.
What can be done to break the chronic stress and weight-gain cycle? I would recommend a dual-pronged approach of stress management through mindfulness meditation and regular exercise to burn fat. Kick-starting an exercise routine will burn calories and also lower stress hormones.
Obviously, to reduce body fat and lose weight, you have to balance your calories in-calories out by exercising more and not overeating. Luckily, by becoming proactive about mindfulness, exercise, and stress reduction simultaneously you can create an upward spiral that increases metabolism and facilitates weight loss.
In 2011, Elissa Epel, who was one of the original researchers to identify the link between cortisol secretion and abdominal fat, conducted a study on the benefits of mindfulness meditation, lowering cortisol, and reducing body fat. Her findings suggest improvements in mindfulness, stress management, and lower cortisol were associated with reductions in abdominal fat.
Mindfulness, meditation, and exercise appear to be an effective triad for minimizing stress and improving your ability to successfully lose weight.
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