It’s easy to assume people with obesity eat more because they simply love food more. However, new research suggests the opposite. In fact, the more weight you gain, the less pleasure your brain actually gets from food. This has to do with the connection between your brain’s level of dopamine and your weight gain, researchers say.
In a new study out of UC Berkeley, scientists uncovered that a high-fat diet dulls the brain’s reward system—specifically by disrupting a chemical pathway tied to dopamine. This is the feel-good signal that helps you enjoy things like music, laughter, and, apparently, a really good snack.
The team studied mice raised on a diet of 60 percent fat. These mice gained weight, but when offered high-calorie treats like peanut butter or chocolate, they weren’t particularly interested. Meanwhile, mice on a normal diet couldn’t get enough of these types of food.
Digging deeper, researchers discovered that the overweight mice had much lower levels of a molecule called neurotensin, which normally helps regulate dopamine. Without it, dopamine didn’t respond properly to food. Even when the scientists tried stimulating dopamine-related brain circuits, it didn’t spark much excitement in the obese mice.
This could mark a shift in how we understand the link between dopamine and weight gain. Instead of overeating for pleasure, many people might be eating out of habit or emotional cues—because the pleasure simply isn’t there anymore.
But here’s the good part: the brain’s response to food isn’t stuck this way. Just like we can rewire the effects of anxiety on the brain, it looks like we can rewire how the brain responds to dopamine, too.
When the mice returned to a standard diet for just two weeks, their dopamine systems bounced back. They started enjoying food again and began losing weight. Another group of mice had their neurotensin levels restored artificially. The results were similar: weight loss, more motivation, and better mood.
This isn’t about a miracle cure for obesity. But it does suggest that restoring healthy pleasure, not suppressing it, could be a smarter way to support long-term change to deal with obesity. Instead of focusing solely on weight-loss drugs or ultra-restrictive diets, future treatments might help people enjoy food again in a way that leads to healthier choices and all without relying on willpower alone.
So yes, losing weight while eating junk food may sound like a fantasy. But rewiring the brain’s reward system? That’s a very real, very promising place to start.
