Obese mice eat less after fasting than lean mice—even when given their favorite food—and this isn’t just because they’re heavier; it’s linked to higher levels of the fat hormone leptin.
Scientific Claim
In mice, diet-induced obesity is associated with reduced fasting-induced re-feeding behavior, which is not fully explained by increased body weight alone and is correlated with elevated plasma leptin levels.
Original Statement
“DIO animals consumed significantly fewer calories when presented with chow after an overnight fast... Plasma leptin was significantly elevated in DIO animals... fasting-induced re-feeding was negatively correlated with leptin levels in DIO animals...”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The study shows correlation between leptin and reduced feeding, but cannot prove leptin causes the effect due to lack of intervention (e.g., leptin blockade). Causal language is inappropriate.
Evidence from Studies
Supporting (1)
Obesity causes selective and long-lasting desensitization of AgRP neurons to dietary fat
When mice get obese from eating fatty food, their brain's hunger signals stop working properly—even after they lose weight—so they don't feel as hungry or eat as much when fasting, and this isn't just because they're heavier.