Both food cravings and food addiction are important components of obesity — and they both start in the brain. This is why researchers have set out to treat binge-eating with a rather extreme, but effective solution by implanting brain stimulation devices directly into the brains of a pair of severely obese patients.
The pilot study proved successful, with the patients losing around 5 kilograms (11 pounds) over the course of six months without any particular dietary restrictions or side effects.
The binge and the brain
Even the most restrained people can fall by the wayside from time to time. What was supposed to be just a few scoops of ice cream quickly ended up revealing the bottom of the container. Who really hasn’t been there? However, for some people, drawing the line when it comes to out-of-control impulse eating is challenging if not impossible. These patients suffer from binge-eating disorder (BED), a mental condition that is now recognized to affect millions across the world to varying degrees of severity.
We often use the word “binge” quite frivolously, either to describe a meal that was much larger than intended or even a long session of Netflix that extends well into the late evening. But in medical terms, binging is far more serious and consequential than Thanksgiving indulgences.
People who genuinely suffer from binge eating find their condition distressing and debilitating. They know they have an eating disorder, but resisting their cravings can be a Herculean task, which makes them fail diets and feel depressed, which enforces a cycle of even more unhealthy excess eating. As such, binge eating causes obesity, type 2 diabetes, high blood pressure, digestive problems, heart disease, and metabolic syndrome, as well as mental conditions like anxiety and depression.
BED was formally added to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) — the ‘bible’ of psychiatry — only in the 2013 edition. However, signs and symptoms of binge eating disorder have been noted in the medical literature since 1932, when German psychoanalyst Moshe Wulff described an eating disorder characterized by binge eating, depression, and disgust with one’s body.
The defining feature of BED is loss of control. The drive for overindulgence is so strong that some patients may consume whatever is in front of them, including entire loaves of bread, frozen fish sticks, and other unprepped bulk foods, regardless of what they might taste like.
Weight loss interventions are ineffective for BED because they don’t address the core problem, which stems from the brain. Previously, scientists had identified a part of the brain called the nucleus accumbens as being linked with impulsive behaviors, including binge eating.
In a new study, researchers implanted deep stimulation devices into the brains of two severely obese patients. Electrodes directly target the nucleus accumbens, delivering electrical stimulation at specific frequencies meant to block brain signals associated with impulsive behavior.
For six months, the implants were kept turned off and the patients were observed closely for any signs of medical problems due to their newly fitted brain implants. Over the course of this period, the researchers closely analyzed the brain patterns of the patients in the lab, looking for signals that are activated by BED. This involved stressful situations in which the patients were presented with appetizing high-calorie foods.
Then the implants were finally switched on, each encoded to deliver high-frequency electrical stimulation to the nucleus accumbens that is customized to each patient, based on their particular BED profile. When BED signals were detected, the implants delivered stimulation to block them, but when there were no cravings, the implant was basically inactive. The BED signals are specifically related to overindulgence behavior and are distinct from normal cravings for food out of hunger.
The therapy seemed to work, with each of the two patients reporting significantly fewer binge-eating episodes. They also lost 5 kilograms (11 pounds) of weight, on average, over six months even though they weren’t asked to restrain from food or keep a diet.
“This was an early feasibility study in which we were primarily assessing safety, but certainly the robust clinical benefits these patients reported to us are really impressive and exciting,” said study senior author Casey Halpern, an associate professor of neurosurgery at the University of Pennsylvania.
One of the subjects improved so much that she no longer met the criteria for binge-eating disorder. Furthermore, there were no obvious signs of adverse side effects.
“This was a beautiful demonstration of how translational science can work in the best of cases,” said study co-lead author Camarin Rolle, a postdoctoral researcher with Halpern’s group.
These are all very promising results, but the researchers urge caution. This is a small pilot study with limited results, which is why they are now enrolling new patients for a much larger study while still keeping a close eye on the two patients in the original study. The good news is that if this treatment is found effective at scale, it can be tweaked to treat other impulsive behavior disorders like bulimia.
The findings appeared in the journal Nature Medicine.