When obese teens have trouble responding to insulin, their hunger hormone doesn't go down as much after drinking a sugary drink compared to lean teens. But if they're obese and still respond well to insulin, their hormone response is just like that of lean teens.

What we've found so far is that obese adolescents who are insulin-resistant tend to have a smaller drop in the hunger hormone acyl-ghrelin after drinking glucose, compared to lean adolescents [1]. Our analysis of the available research shows this pattern is not seen in all obese teens—only in those whose bodies have trouble responding to insulin. The evidence we've reviewed leans toward the idea that insulin resistance, not obesity alone, may play a key role in how the body regulates hunger signals after eating sugar. In one analysis, when obese teens who respond well to insulin consumed a sugary drink, their acyl-ghrelin levels dropped similarly to those in lean teens [1]. But in obese teens with insulin resistance, that suppression was blunted—meaning the hormone didn’t decrease as much. Since acyl-ghrelin helps control appetite, a weaker suppression could mean feelings of hunger don’t decrease as expected after eating. Based on what we've reviewed so far, the data comes from a single assertion supported by 54.0 studies, with no studies refuting the pattern [1]. While the number of supporting studies appears strong, we are still limited by the fact that only one core assertion was analyzed. That means our current understanding is narrow, and more research could change how we interpret these findings. We don’t yet know whether this blunted response directly affects eating behavior or weight over time. Nor can we say whether improving insulin sensitivity would normalize ghrelin responses. Our current analysis only points to a consistent link in the data we’ve examined. Practical takeaway: For some obese teens—especially those with insulin resistance—hunger may not quiet down as much after eating sugar, which could make it harder to feel full. This doesn’t mean weight is out of anyone’s control, but it does suggest body chemistry can vary in ways that affect appetite.