Circadian rhythm and obesity linked

A study published in the most recent version of the journal Obesity found that the body's internal clock, the circadian system, increases hunger and cravings for sweet, starchy and salty foods in the evenings. While the urge to consume more in the evening may have helped our ancestors store energy to survive longer in times of food scarcity, in the current environment of high-calorie food, those late night snacks may result in significant weight gain.

Eating a lot in the evening can be counterproductive since the human body handles nutrients differently depending on the time of day. For example, sugar tolerance is impaired in the evening. Additionally, consuming more calories in the evening predisposes people to more energy storage; we simply don't expend as much energy after an evening meal in comparison to morning meals.

Furthermore, artificial light enables people to stay up later than they probably should and often people don't get enough sleep. If you stay up later, during a time when you're hungrier for high-calorie foods, you're more likely to eat during that time. You then store energy and get less sleep, both of which contribute to weight gain.

The researchers say that knowing how your body operates will help you make better choices. Going to bed earlier, getting enough sleep and choosing lower-calorie foods rather than higher-calorie foods in the evening can all help with weight loss. Because of the internal circadian regulation of appetite, we have a natural tendency to skip breakfast in favor of larger meals in the evening. This pattern of food intake across the day, according to researchers, is exactly what Sumo wrestlers do to gain weight. Yikes!