Managing Your Weight in The Dark

Readers will recall a post earlier this week on the importance of sleep for weight management.

Researchers and clinicians, wanting to know more about the underlying biology and mechanisms on how lack of sleep, disruption of circadian rhythm (e.g. through shift work, jet lag, or having a baby), and alterations in light/dark cycles can impact ingestive behaviour and energy metabolism may wish to read a comprehensive review just published in the Annals of Medicine.

In this paper, Russel Reiter and colleagues from the University of Texas, San Antonio, summarize the potential contributions of three processes that may be contributing to humans becoming progressively more overweight: circadian or chronodisruption, sleep deficiency, and melatonin suppression.

As the authors point out:

Circadian disruption, sleep deficiency, and melatonin suppression have at least one common causative feature, i.e. excessive light exposure including even brief periods of light at night. Indeed, interrupting the normal dark period with a short interval of bright light may be the most disruptive. Certainly, light pollution throughout the world, and especially in the economically well developed and developing nations, where obesity is also the most common, has become a major problem and is a serious concern. The use of artificial light after darkness onset in the evening and in the morning before sunrise is commonplace and impacts the physiology of the circadian system which influences both nocturnal melatonin synthesis and sleep. Moreover, being exposed to light after darkness onset due to what is referred to as trespass light or intentionally turning on a lamp is disruptive to the circadian system, which reduces melatonin levels and disturbs sleep.

Obviously, looking at bright light sources such as a TV, a computer screen or a backlit e-Book can be even more disruptive.

Perhaps we should now all plan for candle-light dinners and then call it an early night?

Leipzig, Germany

Reiter RJ, Tan DX, Korkmaz A, & Ma S (2011). Obesity and metabolic syndrome: Association with chronodisruption, sleep deprivation, and melatonin suppression. Annals of medicine PMID: 21668294