It seems counterintuitive. But many obese people don’t get pleasure from eating fatty foods. Now, researchers have learned why.
This phenomenon was seen in mice for years. When mice ate a fatty diet, they stopped enjoying food but ate more. However, it wasn’t studied in humans, and scientists have never understood why it happened. This study looked at humans and learned what happens in the brain.
A new study found that people with obesity have low levels of a brain chemical that activates dopamine. The chemical, neuropeptide neurotensin (NT), can influence appetite. The rich, fatty foods don’t spark the pleasure in their brains that singles reward. Instead, they may eat out of boredom and habit, not getting a cue to stop.
Eating a high-fat diet for an extended period reduces NT in humans. That can contribute to the progression of obesity as food stops being pleasurable and becomes more addictive as the brain seeks pleasure.
“A natural inclination toward junk food is not inherently bad — but losing it could further exacerbate obesity,” said Stephan Lammel, an associate professor of neurobiology at UC Berkeley who led the research.
The researchers hope that this study could lead to new weight loss treatments. “Upregulating” NT could help people enjoy food more. If they felt rewarded when eating something calorific, that may help them feel satisfied and help them eat less. Researchers need to learn if the potential treatment could come through a special diet or genetic manipulation.
“What’s especially compelling is that restoring neurotensin levels — either by switching back to a regular diet or through targeted genetic approaches — can bring back that sense of reward,” said Prof. Lammel. “This not only increased feeding motivation in specific contexts, but also normalized weight gain, improved mobility and reduced anxiety.”
Helping people feel pleasure while eating could break a cycle of pleasure-seeking and help them feel satiated. Prof. Lammel explained, “If food becomes pleasurable again in a meaningful and regulated way, the body may naturally recalibrate toward healthier patterns of intake.”
Popular weight loss medications are designed to make people feel full. They don’t look at the reason people eat when they aren’t hungry. This approach wouldn’t be based on suppressing appetite. Instead, it would aim to make food more enjoyable and help people stop chasing the happy feeling they get from dopamine.
