Researchers from the University of Southern California gathered their findings from an experiment that tested lab rats. Compared to other rats, those that were prone to obesity because of genetics, showed brain structures that resulted in a lower sensitivity to the hormone, leptin, which is also responsible for fat metabolism.
The different brain structure was found in the hypothalamus, which experts have tagged as the part of the brain responsible for the regulation of body conditions.
The experiment also showed that although the obese rats were put through exercise and other weight-reducing activities, the risk of regaining any lost weight was greater.
"It seems that appetite and obesity are built into the brain," the AFP quoted Sebastian Bouret of the University of Southern California.
"The neurodevelopmental differences in these animals can be seen as early as the first week," he added, relating the results to human biology. "The results show that obesity can be wired into the brain from early life."
Richard Simerly, another researcher for the study, said that based on the findings, people who are genetically wired for obesity must be very careful about energy expenditure and diet, as according to Bouret, the propensity cannot be reversed.
WebMD explained further, saying that obese-prone rats had to exert extra effort to avoid obesity, as their bodies are not as responsive to signals of fullness.
"It is increasingly accepted that obesity results from a combination of genetic and environmental factors," said the study.
Simerly noted that based on the findings, the mindset that nutrition and lifestyle are the only factors that affect weight "does a disservice to people whose biology predisposes them to obesity."
The study is published in the February issue of the journal Cell Metabolism.
