Alternate day fasting decreases preference for a calorically dense diet by increasing chow intake and altering meal pattern parameters.

Alternate day fasting (ADF) is an effective dietary strategy for weight loss in both humans and rats. However, fasting can elicit hyperphagia in rats, particularly upon access to a calorically dense, high-energy (HE) diet. To examine the effects of ADF on HE diet preference, male and female Sprague-Dawley rats were randomly assigned to receive either ad-libitum or alternate day access to both chow and HE food. Meal pattern analysis was conducted to provide a more detailed explanation of changes in HE preference. ADF rats had a decreased preference for the HE diet compared to controls. Both male and female ADF rats increased in overall intake of chow. However, for male ADF rats, the decrease in HE preference was driven by an increase in both size and number of chow meals; for females, it was driven only by an increase in number of chow meals. Meal size is controlled by both positive feedback (e.g., from the oral cavity) and negative feedback (e.g., from postoral inhibitory signals). Thus, for males, fasting appeared to increase orosensory stimulation and/or decrease sensitivity to inhibitory cues towards chow. For females, fasting appeared to decrease sensitivity to inhibitory cues towards chow. The decrease in HE preference observed in the current study may contribute to the effectiveness of ADF as a dietary strategy for weight loss.