We all have an internal “clock” which drives our circadian rhythm (the natural internal process that regulates our sleep-wake cycle during a 24-hour period). External light levels, eating times and physical activity all act to keep the body clock synchronised to the external environment.
But our circadian rhythm can be disrupted by any number of factors, including going to bed later than usual, or eating late at night. While occasional disruptions are no cause for alarm, research shows that long-term circadian rhythm disruption can cause poor health. For example, many studies have found that regular shift work increases the risk of obesity and type 2 diabetes. And unfortunately, circadian rhythm disruption is becoming more common in our society, thanks in part to light pollution, noise and electronic devices, all of which could increase instances of these chronic health conditions.
But why is the body able to manage one-off instances of circadian rhythm disruption – such as staying up late on the weekend, or eating a late-night meal – without any health consequences? This study looking at how the circadian rhythm controls metabolic processes to match our daily patterns of food intake holds the answer.
An awesome protein in the liver called REVERBα acts to smooth out the effects of disordered eating, as shown in our diagram below.
In this way, all the internal clocks embedded in our body’s tissues serve to protect against occasional changes in behaviour (such as the odd late-night meal). However, when we are constantly doing things that go against our natural circadian rhythm – such as always eating late, or working night shifts – this protective system is overwhelmed, leading to obesity and diabetes.
The study, therefore, highlights the importance of eating meals in sync with the body clock, during the day. To keep our liver clock ticking – and to keep our whole circadian rhythm working properly – it’s important to develop an eating schedule that has a clear separation between the fed period (typically during the day), and the fasted period (typically during the night). This is hard for shift workers, depending on shift schedule, so strategies to help are urgently needed.
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