Most mice sleep, eat, and exercise on a predictable 24-hour cycle, thanks to their precise internal clocks. But mice fed a fatty diet have trouble sticking to their schedule, new research shows. Genetic activity, not just behavior, drives the changes.
Understanding this novel link between daily cycles, known as circadian rhythms, and the metabolic system could help reveal the mechanism behind some cases of obesity and diabetes in humans, scientists say.
Earlier research had shown a connection between circadian rhythm and eating behavior. For example, mutations in mouse genes that help maintain the internal clock's rhythm cause the animals to overeat and gain weight. Studies have also shown that people who work night shifts are at higher risk for obesity than their day-shift counterparts, and that getting too little sleep can raise a child's risk of developing diabetes later in life.