SEASONAL RHYTHMS OF HUMAN NUTRIENT INTAKE AND MEAL PATTERN

Seasonal variations in the nutrient intakes and the meal patterns of humans were investigated by paying 315 adult humans to maintain a 7-day diary of everything they ate, when they ate it, and their subjective state of hunger. A marked seasonal rhythm of nutrient intake was observed with increased total caloric intake, especially of carbohydrate, in the fall, associated with an increase in meal size and a greater rate of eating. The subjects rated themselves hungrier at the end of the meal in the fall even though the larger meals resulted in a greater estimated amount of food in the stomach. In the winter and spring there was a strong negative relationship between the amount eaten in the meal and self-rated hunger at the end of the meal. This correlation was absent during the fall. The results suggest that even with modern heating and lighting seasonal rhythmicity of food intake persists in humans and is a major influence on eating that may act by suppressing satiety mechanisms.