It is common to assume that individuals who are overweight derive more pleasure from food compared to those with smaller bodies, but this is not accurate. Instead, individuals tend to experience increased pleasure from their diet as they gain weight.
Researchers have now identified the reasons behind this phenomenon, as well as how restoring the pleasure response can be facilitated by adopting a healthier diet.
“Obesity is often associated with an excessive enjoyment of food. People believe they cannot resist unhealthy food options,” explained Professor Stephan Lammel, a neuroscientist at the University of California, Berkeley and the senior author of the study, in an interview with BBC Science Focus.
“However, both our research and previous studies indicate the opposite: Over time, individuals may experience a decrease in food-related pleasure.”
These findings are linked to the role of dopamine, a brain chemical associated with rewards, motivation, and pleasure. Researchers have discovered that overweight mice have lower levels of a molecule called neurotensin, which impacts dopamine responses to food.
“Contrary to popular belief, individuals with obesity may not eat for pleasure. In reality, much of their eating habits are influenced by routines and emotional cues rather than pleasure or desire,” Lammel added.
To investigate this further, researchers fed a group of mice a high-fat, unhealthy diet and observed their eating behavior. The results showed that the mice preferred the high-fat diet over regular low-calorie foods, indicating a preference for unhealthy options.
However, when presented with high-calorie treats like butter, peanut butter, and chocolate, the mice showed less interest compared to those on a normal diet. This suggests that their food choices were driven by habits rather than pleasure.
Further experiments involving stimulating brain circuits connected to dopamine yielded interesting results. While normal weight mice responded positively to the treatment, overweight mice did not, indicating an issue with dopamine and neurotensin levels.
The researchers were able to correct this by switching some mice to a normal diet, resulting in a return to normal levels of neurotensin, dopamine function, and interest in high-calorie foods. Additionally, artificially restoring neurotensin levels in other mice led to weight loss and improved food motivation, mood, and mobility.
“Our findings suggest that targeting neurotensin signaling through genetic strategies could help rebalance food motivation and promote healthier eating habits,” Lammel stated.
It is important to note that this study was conducted on mice fed high-fat diets, so the results may not directly apply to obese individuals. Nevertheless, the implications for human health are promising.
When asked about the potential impact on people, Lammel commented, “It could potentially make it easier for individuals to maintain a healthy weight without solely relying on willpower or restrictive diets.”
About our experts
Stephen Lammel: Associate Professor of Neurobiology at the Department of Neuroscience at the University of California, Berkeley. Investigator at Weil Neurohub with a focus on neural circuits mediating motivation and reward. Member of the Helen Wills Neuroscience Institute.
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Source: www.sciencefocus.com
