When it comes to losing weight, some of the most common advice out there is “portion control,” at least when people aren’t trying to promote some combination of foods that will somehow set the process of weight loss in motion. There’s probably some good advice in all of these helpful hints, but they’re not always easy to pay attention to when faced with the desire to overeat, or when we find ourselves in the process of doing just that. The key to understanding what causes us to overeat may, in fact, lie within the brain.
There is a growing trend to treating obesity as an epidemic across the globe, as its rate has tripled internationally since 1975, according to reports from the World Health Organization. This is because of the increased risk of cardiovascular disease, type 2 diabetes, developing several forms of cancer, and at the time of the pandemic, it makes individuals more susceptible to the effects of COVID-19. While calorie-rich food and a general lack of daily physical activity over the last four decades are the primary culprits of this epidemic, which has affected 42% of adults in the U.S. yearly, an international team of researchers assembled by the University of Florida in Gainesville sought to explore what role our minds play in all of this.
In the way that most animals have evolved over time to increase their energy intake to their full advantage, so have our own brains. The researchers’ latest experiment suggests that the reason we’re always sneaking downstairs for that midnight snack might be due to a region of the brain called the infralimbic cortex (IL), located in the frontal lobe of the brain’s cerebral hemisphere. Involved in emotional responses and acting like something of a switchboard to the brain’s amygdala, the IL serves a function in how we learn to seek out food and feed ourselves — a reason why dietitians advise us to keep high-calorie snack out of clear view when storing them in the kitchen.
Tempted With Dessert
A primary reason you might overeat that coincides with the basic operations of the IL is that you are simply exposed to environmental cues that might make you think of treats, according to Dr. Sergio Iñiguez, a member of the team who also serves as the director of the Iñiguez Behavioral Neuroscience Lab at the University of Texas at El Paso. Think of those times at the dining hall where you probably had one or two portions of dinner and felt full, but then you saw cookies or a new German chocolate cake being put out in the display case, and decided you could probably still make room for some?
Iñiguez and his fellow researchers learned that they could stop this sort of behavior in lab rats just by deactivating the animals’ IL. They switched off this cortical structure just after they conditioned the rats to associate pulling a lever in their cages with receiving a treat. Once the IL was inactive, the rats simply lost interest.
For too many of us, we’ve all got that comfort food associated with a calming response — one that takes us back to the first time we ever had fresh baked cookies or a peanut butter sandwich — and realized that we calmed ourselves by satisfying our hunger with these particular food items.
“This is a big discovery because we now have experimental tools that allow us to turn off neurons while the subjects engage in a specific behavior,” says Iñiguez.
The research put together by his team has now made the circuitry that makes this connection much clearer. Their findings were published by the journal eNeuro. Iñiguez and his colleagues hope that the discovery could lead to targeted strategies to prevent patients from overeating.
Rewarding Ourselves With Food
The scientists first trained the lab rats to press a lever in order to get a treat. When they pulled the lever, the food fell into their cage, and simultaneously, a light came on, giving the rats a cue. Some rats were quick to learn, others less so. Brain scans suggested that the ones who picked up on it sooner, had stronger connections in their brains between the IL and other neurons, than the rats who took more time to figure it out. When they deactivated the IL in these fast learners, they became more reluctant to pull the lever for their treats.
The researchers concluded that IL neuronal connections are formed when the rats found a new way to acquire food and nutrients, and determined that the connections become active when seeking out food, shedding light on where to look when trying to find clinical applications to stopping overeating — but perhaps looking at this study is a chance to see overeating in a different light than just deciding that we do it because we lack the willpower.
