Why do some people feel full after a few bites while others never seem to lose the urge to snack? New research from the University of Tartu in Estonia suggests that the answer may lie deep in our genes.
The study, published in Nature Communications, analyzed genetic data from more than 200,000 Estonian adults to explore how tiny variations in DNA can influence appetite, metabolism and body weight. Instead of identifying a single “obesity gene,” scientists found that many genes each play a small role, together shaping how the brain and body regulate hunger.
Lead researcher Erik Abner, a functional genomics expert at the University of Tartu, said the team focused on the youngest recorded body mass index data because genetic influences are most visible early in life.
“As people grow older, environmental factors like diet and lifestyle begin to play a greater role,” he said.
Among the findings were two appetite-related genes with opposite effects. A variant in the MC4R gene, found in about 3.5% of Estonians, was linked to lower appetite and body weight. Meanwhile, a rarer variant in the POMC gene, present in fewer than 1% of participants, was associated with higher appetite and slower satiety, leading to modest but measurable increases in weight.
Researchers noted that a similar variant in Labrador Retrievers increases appetite and food motivation, helping explain why that breed is especially prone to weight gain. The comparison offers a striking example of how shared genetic mechanisms can shape appetite across species.
The study also linked body weight to genes involved in brain signaling, including ADGRL3 and PTPRT, which have previously been associated with attention and learning. These new connections suggest that the nervous system plays a larger role in weight regulation than once thought and could become a target for future obesity treatments.
The team’s next project will examine how obesity drugs such as semaglutide affect people with these genetic variants. Since semaglutide works on appetite-regulating hormones, its effectiveness may vary by genetic profile, bringing researchers closer to the goal of personalized weight-loss medicine.
This research was supported by the Estonian Research Council and the University of Tartu Institute of Genomics.