Predicting and Classifying Rats Prone to Overeating Fat

The availability and overconsumption of palatable foods rich in fat likely contribute to the worldwide obesity epidemic. With environmental factors and genetic predisposition each playing important roles in this serious health problem, it is crucial to identify and properly treat individuals who have a greater propensity to eat excessive amounts of fatty foods. Animal studies have been instrumental in this regard, allowing researchers to identify and examine early behavioral or physiological factors that are positively associated with and can predict future fat consumption and obesity. The methods for classifying and subgrouping these animals, which are described herein, focus on three early predictive measures, namely, 5-day fat intake, novelty-induced locomotor activity, and fat-induced triglyceride levels, which have all been successfully used to identify outbred rats that are prone (i.e., have higher propensity) or resistant to overeating fat. The early identification based on these three factors of animals prone to overeating fat, in conjunction with tests to characterize their specific phenotype, can yield valuable information regarding the underlying behavioral, physiological, and neurochemical pathways involved in driving excessive fat intake, ultimately leading to an obese state.