Weekly rhythms of spontaneous nutrient intake and meal pattern of humans.

Weekly variations in the nutrient intakes and the meal patterns of humans were investigated by paying 323 adult humans to maintain a 7-day diary of everything they ate, when they ate it, and their subjective states of hunger, depression, and anxiety. A marked weekly rhythm of nutrient intake was observed, with a greater total caloric intake and larger meal sizes on weekends associated with an increase in the duration of the meals and the number of other people present. The number of other people present had both significantly larger univariate correlations with meal size and multivariate Beta coefficients predicting meal size on weekends than on weekdays. The results support a hypothesis that the heightened intake on weekends results from increased social facilitation of intake resultant from a greater number of other people present at weekend meals and a greater flexibility to extend the duration of the meals on weekends.