The pleasure we get from eating junk food — the dopamine rush from crunching down on salty, greasy French fries and a luscious burger — is often blamed as the cause of overeating and rising obesity rates in our society.
But a new study by scientists at the University of California, Berkeley, suggests that pleasure in eating, even eating junk food, is key for maintaining a healthy weight in a society that abounds with cheap, high-fat food.
Paradoxically, anecdotal evidence suggests that people with obesity may take less pleasure in eating than those of normal weight. Brain scans of obese individuals show reduced activity in pleasure-related brain regions when presented with food, a pattern also observed in animal studies.
Now, UC Berkeley researchers have identified a possible underlying cause of this phenomenon — a decline in neurotensin, a brain peptide that interacts with the dopamine network — and a potential strategy to restore pleasure in eating in a way that helps reduce overall consumption.
The study reveals an unsuspected brain mechanism that explains why a chronic high-fat diet can reduce the desire for high-fat, sugary foods, even when these foods remain easily accessible. The researchers propose that this lack of desire in obese individuals is due to a loss of pleasure in eating caused by long-term consumption of high-calorie foods. Losing this pleasure may actually contribute to the progression of obesity.
“A natural inclination toward junk food is not inherently bad — but losing it could further exacerbate obesity,” said Stephan Lammel, a UC Berkeley professor in the Department of Neuroscience and a member of the Helen Wills Neuroscience Institute.