Self-control has always been a key ingredient in successful weight loss. Overcoming temptation and keeping hunger in check play key roles in the weight loss journey. Research has now shown that specific brain regions, especially those involved with self-regulation and motivation have important roles as well.
What role, if any, do higher-level brain functions have in successful weight loss? What connected factors impact those roles, if they exist?
These were the questions asked by Alain Dagher of the Montreal Neurological Institute and Hospital in Canada. He and his team studied 24 patients in a weight-loss clinic and found that those who had the best success losing weight showed more activity in the lateral prefrontal cortex, an area of the brain linked with self-control.
Daigher said of the findings, “What we found is that in humans, the control of body weight is dependent largely on the areas of the brain involved in self-control and self-regulation,” That area of the brain has the ability to take into account long-term information, such as the desire to be healthy, in order to control immediate desires.”
Part of the puzzle has to do with two key hormones related to eating, hunger and weight loss. Ghrelin tells the brain when it’s time to eat, while leptin signals the brain when enough food has been eaten. Levels of these two hormones can change quickly when a person loses weight.
“Everybody who loses weight sees this change in leptin and ghrelin,” says Dagher. “It is just that some people, for reasons we do not know, are able to maintain their self-regulation in the face of that signal.”
Before beginning their weight-loss diets, each of the participants had a functional MRI (fMRI) study done of their brains. The scans focused primarily on the lateral prefrontal cortex, which is associated with self-regulation, and the ventral medial prefrontal cortex, which is linked to motivation, value and desire.
Throughout the study period of three months, researchers showed the participants photos of appetizing foods, along with pictures of scenery as a control. They then compared the activity in the subjects brains in response to the food pictures, especially those photos of high-calorie foods. This was done at baseline, at one month and again at three months. “When we show pictures of appetizing foods, the ventral medial prefrontal cortex area becomes more active on fMRI,” Dagher says.
That is interesting in and of itself. What might be more interesting, though, is what happened in the two key brain regions being looked at in the people with the greatest weight loss success. At months one and three, the signal from the ventral prefrontal cortex (desire) declined, while that from the lateral prefrontal cortex (self-control) rose.
“In the fMRI, the self-control area increased its activity and the value area decreased its activity,” says Dagher. “And the amount of change was predictive of successful weight loss.” While all participants lost weight, those who achieved the greatest weight loss had fMRI levels indicating a better ability to self-control. And, at the end of the 3-month study, the hormones ghrelin and leptin were starting to return to baseline, suggesting that a new set point was achieved.
“These results suggest that weight loss treatments that increase self-control, such as cognitive behavioral therapy, may be helpful, particularly when stress is involved in leading to overeating,” he says. “Stress disrupts the lateral prefrontal cortex control mechanism, but you may be able train people to seek a different strategy.”
Assessing the role of hormones in weight loss, as well as what role various brain regions play, is a complex matter. Emotional factors, stress, intellectual conditioning and a host of other factors can play havoc with hormone balances and activity. But understanding the relationship between the brain regions that influence self-control and desire certainly begins to make the whole weight loss success picture a little clearer.
Knowing if there is a neuro-hormonal connection between activity in these regions and the digestive hormones ghrelin and leptin could go a long way toward helping us build better psychological and emotional support mechanisms for those seeking weight loss. The brain runs the body. The more we know about how it works and what it influences, the better chance we’ll have for long life and good health!
Keep the faith and keep after it!
Journal Reference – Selin Neseliler, Wen Hu, Kevin Larcher, Maria Zacchia, Mahsa Dadar, Stephanie G. Scala, Marie Lamarche, Yashar Zeighami, Stephen C. Stotland, Maurice Larocque, Errol B. Marliss, Alain Dagher. Neurocognitive and Hormonal Correlates of Voluntary Weight Loss in Humans. Cell Metabolism, 2018; DOI: 10.1016/j.cmet.2018.09.024