Fat from Food Tricks Brain Signals

Fat molecules cause the brain to send messages to the body’s cells, warning them to ignore the appetite-suppressing signals from leptin and insulin, hormones involved in weight regulation, according to a new study from UT Southwestern Medical Center. Researchers also found that one particular type of fat—palmitic acid that is found in butter, cheese, milk and beef—is particularly effective at triggering this mechanism.

“Normally, our body is primed to say when we’ve had enough, but that doesn’t always happen when we’re eating something good,” said Dr. Deborah Clegg, assistant professor of internal medicine at UT Southwestern and senior author of the rodent study appearing in the September issue of The Journal of Clinical Investigation.

“What we’ve shown in this study is that someone’s entire brain chemistry can change in a very short period of time. Our findings suggest that when you eat something high in fat, your brain gets ‘hit’ with the fatty acids, and you become resistant to insulin and leptin,” Clegg said. “Since you’re not being told by the brain to stop eating, you overeat.”

Clegg said that in the animals, the effect lasts about three days, potentially explaining why many people who splurge on Friday or Saturday say they’re hungrier than normal on Monday.