New research suggests that consuming a diet that is high in fat can lead to overeating.
Researchers from the Neuroscience Program in Substance Abuse (N-PISA) at Vanderbilt University found that defective signaling in the brain can cause overeating of high fat foods in mice, leading to obesity.
Worldwide, obesity has more than doubled since 1980. Today around two billion people are overweight, and 600 million of these are obese. A number of factors contribute to the obesity epidemic, including economic stresses, changes in the built environment and changing food trends.
"We have always been struck by how much animals -- and even people -- will over-consume tasty high-fat foods, even though they might be technically feeling full," Dr. Aurelio Galli, one of the authors of the study, said in a statement. "A high fat diet causes people to eat more, which ultimately impairs the ability of obese people to successfully control their caloric intake, lose weight and maintain weight loss. We have conducted several studies trying to understand why a high fat diet has this effect."
For the study, researchers looked at one particular signaling pathway in the brain -- insulin signaling -- and the way it works in specific brain cell circuits. Defects in insulin signaling can override the body's natural homeostatic mechanisms in favor of the reward mechanisms, leading to obesity.
"Our findings reveal a system that is designed to control eating of rewarding foods that are high in fat and possibly sugar," Galli said. "This system can be hijacked by the very foods that it is designed to control. Eating a high-fat or high-carbohydrate diet feels rewarding, but also appears to cause changes in the brain areas that are involved in controlling eating, by causing for example insulin resistance. Our study shows that when specific signaling in these areas of the brain is disrupted, it leads to a vicious cycle of increasing, escalating high-fat diet intake that likely further cements changes in these brain areas."
The findings are detailed in the journal Heliyon.
