Why People Crave Evening Snacks
Researchers report that they may have found an explanation on why many people consume more food late in the evening but are less likely to eat breakfast. The study, published recently in the journal Obesity, found that the body’s internal clock, or the circadian system, increases hunger and cravings for high-calorie foods such as starchy, sweet, and salty foods at night. They explain that urge to consume more calories in the evening may have been helpful for early man to store energy to survive in times of food scarcity. However, in current times, late night snacking may result in significant weight gain.
Author Steven Shea, Ph.D., director for the Center for Research on Occupational and Environmental Toxicology at Oregon Health & Science University clarifies that although there are many factors that affect weight gain, such as diet and exercise, the time of eating also affects weight gain.
The study evaluated the appetite and food preferences of 12 healthy non-obese adults for 13 days in a laboratory with very dim light. All behaviors were scheduled, including meal times and sleep time. Frank Scheer, Ph.D, first author on the study, explains that all of the participants’ meals and activities were scheduled evenly across the day and night to allow examination of the effects of true internal circadian, while other effects on appetite such as the amount of food recently consumed were controlled.
The investigators found that the participants felt the least hungry at 8 o’clock in the morning and most hungry at 8 pm. Appetite for different types of food and the amount of food they ate were also influenced by these internal rhythms. The researchers concluded that the internal circadian system causes appetite to peak in the evening, which may promote eating of larger, higher-calorie meals before sleep, which necessitates fasting.
The researchers also explained that rates of metabolism may depend on the time of day since sugar tolerance is lower in the evening while energy storage is higher, contributing to weight gain.
Oregon Health & Science University. What triggers those late-night snack cravings?. ScienceDaily.