OBJECTIVES: We have shown that whole egg consumption reduced cumulative body weight gain in the Zucker diabetic fatty (ZDF) rat, a genetic model of obesity and type 2 diabetes (T2D), but was without effect on body weight gain in lean control rats. Thus, we hypothesized that whole egg consumption would reduce cumulative body weight gain in a diet-induced model of obesity (DIO) using a high-fat, high-sucrose (HFHS) diet (60% and 11% total kcal from fat and sucrose, respectively).
METHODS: Male Sprague-Dawley rats (5 wk of age; n = 24) were randomly assigned to 1 of 4 treatment groups: control rats fed a casein-based diet; control rats fed a whole egg–based diet; DIO rats fed a casein-based HFHS diet; and DIO rats fed a whole egg–based HFHS diet. All rats were fed their respective diets for 33 wk, and food intake was measured for the final 3 wk of dietary treatment. Mean values from all analyses were compared using a one-way ANOVA (P < 0.05).
RESULTS: In contrast to our previous studies using ZDF rats, DIO rats fed a casein-based HFHS diet did not exhibit metabolic characteristics of T2D, such as hyperglycemia or hypertriglyceridemia. An obese phenotype was achieved as the cumulative body weight gain in DIO rats fed the HFHS casein-based diet was ∼26% higher than the body weight gain in control rats fed the casein- and whole egg–based diets. However, whole egg consumption in DIO HFHS-fed rats reduced the body weight gain by 24% compared with the DIO rats fed the HFHS casein-based diet. Moreover, the body weight gain did not differ between the DIO rats fed the HFHS whole egg–based diet and the control rats fed the casein- and whole egg–based diets. Despite a higher body weight gain in DIO rats fed the HFHS casein-based diet, total food intake per 100 g body weight was 12% higher in the DIO rats fed the HFHS whole egg–based diet compared with the DIO rats fed the HFHS casein-based diet. In contrast, total food intake per 100 g body weight did not differ between the control rats fed the casein- or whole egg–based diet.
CONCLUSIONS: Similar to our findings in a genetic model of obesity and T2D, these data suggest that whole egg consumption reduces body weight gain in a diet-induced model of obesity, whereas body weight gain is not altered by whole egg consumption in a lean phenotype. Furthermore, the reduction in body weight gain exhibited by DIO rats appears to be independent of a diabetic state.
