Overeating by Young Obesity-prone and Lean Rats Caused by Tastes Associated With Low Energy Foods
2007
Pierce, W David | Heth, C Donald | Owczarczyk, Joanna C. | Russell, James C. | Proctor, Spencer D.
OBJECTIVE: Childhood obesity is a prominent health problem that may involve early learning about tastes and the energy content of foods. We tested the hypothesis that food tastes predictive of low energy content cause overeating in young animals. RESEARCH METHODS AND PROCEDURES: Juvenile and adolescent (4- and 8-week-old) male JCR:LA-cp lean (+/cp or +/+) and obesity-prone (cp/cp) rats were given sweet (saccharin) and salty (sodium chloride) gelatin cubes made with starch (high caloric) or no starch (low caloric) for 16 days of taste conditioning. After 10 hours of food deprivation, rats received pre-meals with flavors that had been paired or unpaired with high caloric content during taste conditioning, followed immediately by measurement of chow intake at regular meals. RESULTS: Our findings show that both lean (+/cp) and obesity-prone (cp/cp) juvenile rats ate more regular chow after a pre-meal with a flavor associated with low caloric value than after a similar pre-meal with a flavor predictive of high caloric content. This effect occurred with juvenile rats but not with adolescents. DISCUSSION: Data from our study indicate that the subversion of the relationship between taste and caloric content disrupts the normal physiological and behavioral energy balance of juvenile rats, resulting in overeating that is independent of genetic disposition for obesity.
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