Clinical Brown Bag

Nicole M. Avena, Ph.D., University of Florida, Center for Addiction Research and Education, College of Medicine

Thursday, March 14, 2013, 12:00 pm – 1:00 pm
3021 East Hall

Event Information

Abstract:

The increase in the prevalence of obesity, along with the convenient availability of highly-palatable, calorically-dense foods, has led some to suggest that hedonic hyperphagia may be a cause of increased body weight. It is well known that overeating of palatable food can have powerful effects on brain reward systems, however, it is debated whether excessive intake of palatable food can produce signs of dependence such as those seen in response to drugs of abuse. In an effort to better understand this concept, several studies have been conducted using laboratory animal models to assess whether overeating of palatable foods can produce behaviors and changes in reward-related brain systems that are similar to those seen with some drugs of abuse. In the case of binge consumption of 10% sucrose, observed behaviors include tolerance, signs of opiate-like withdrawal, enhanced motivation to obtain sucrose, and a heightened sensitivity to, or consumption of, drugs of abuse. Accompanying brain changes include alterations in dopaminergic, cholinergic and opioid systems in the nucleus accumbens, which are similar to the effects seen in response to some drugs of abuse. While rats bingeing on sucrose show these behavioral and neurochemical signs of addiction, they maintain a normal body weight. However, studies addressing overconsumption of palatable foods have been extended to compare the effects of overeating a variety of nutrients and palatable foods in addition to sucrose. Findings produced by these studies show that when rats overeat fat-rich diets they can gain excess body weight, but different behavioral signs of addiction are seen. Recently, clinical studies have used psychometrics and brain imaging techniques to study overeating within clinical populations. The results of these studies also suggest that aspects of drug-like dependence can be observed in response to excessive intake of palatable foods in some individuals. Collectively, these findings show aberrant behaviors and brain changes that can develop when rats or humans excessively eat palatable foods, and suggest differences in aspects of addiction that emerge when body weight and the type of palatable food are considered.