Meal patterns of macronutrient intake in rats with particular dietary preferences

In the present study, we examined, via computer-assisted analyses, the nocturnal meal patterns of male albino Sprague-Dawley rats with clear differences in their individual preferences for the macronutrients, protein, carbohydrate, and fat. Rats exhibiting a strong preference for the carbohydrate diet over the 12-h nocturnal cycle (approximately 50% of the group) consumed fewer total calories and relatively small, more frequent meals, compared with rats that preferred protein or fat. Moreover, the first meal of the feeding cycle was identified as being most distinctive in reflecting the individual dietary preferences of these rats. This contrasts with the subsequent meals, which for all rats showed a general trend of increasing proportions of protein and fat and a decreasing concentration of carbohydrate. Only the high-fat rats (approximately 30% of the group) were further distinguished by a particularly large fat-predominant meal in the middle-dark period, which was then followed by smaller fat-rich meals in the late-dark period. These fat-preferring rats exhibited significantly greater body weight gain compared with rats preferring carbohydrate.(ABSTRACT TRUNCATED AT 250 WORDS)