Sensory responses, dietary-induced obesity and biochemical values in Sprague-Dawley rats

Food intake and body weight gain variability in Sprague-Dawley (SD) rats exposed to a palatable high-fat diet were examined in relation to sensory responses and biochemical parameters in two experiments. In the first experiment, varying sucrose concentrations (4-32% wt./vol.) were randomly presented for 20 minutes to ad lib chow-fed rats. Each rat's sensory response was expressed as Beta (B), or the slope of the regression between solute intake and concentration, and used to assign rats to diet groups. In the second experiment, responsiveness to fat emulsions (1-37%) were similarly measured and categorized. In both experiments sensory responses to sucrose were significantly related to weight gain/fatness on the high-fat diet (lab chow-corn oil). Sensory responsiveness to the fat emulsions was unrelated to sucrose responsiveness or to high-fat feeding. Biochemical parameters (insulin, cholesterol, triglycerides, lipoproteins) reflected increased caloric (fat) intake, as well as sucrose responsiveness. Predictors (sensory responses, biochemical values) of response to chronic (4 months) or short-term (less than 2 months) high-fat diets are discussed.