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Blue Light Exposure Before Dinner Increases Your Hunger

Blue-enriched light exposure immediately before the evening meal may increase hunger, according to a new study published in the journal Sleep.


Blue light may increase hunger. Image credit: Alexofdodd / CC BY-SA 3.0.

Ten healthy adults were recruited into a study group in which they were given the same carbohydrate-rich isocaloric meals with regular sleep and eating schedules.

In a four-day experiment under dim light conditions, they were exposed to less than 20 lux during the period of 16 hours when they were awake and less than 3 lux during eight hours in the period of sleep.

On day three they were under exposure of three-hour 260 lux, blue-enriched light beginning 10.5 hours after being awake. And then the effects were examined in comparison of that under dim light exposure on day two.

The result of the study demonstrated that in comparison with dim light exposure, blue-enriched light exposure was closely linked with an increasing hunger that started just 15 minutes after light exposure and it would continue for nearly two hours even after the meal.

As Dr Ivy Cheung, a neuroscientist at Northwestern University in Chicago, Illinois, and the first author of the study said, the observation was quite interesting that the exposure to blue-enriched light for just three-hour in the evening could make a big impact on hunger and glucose metabolism

In addition, blue light exposure also cut down sleepiness and caused the higher measures of resistance in insulin.

According to Dr Cheung, such results are of importance in regard to the suggestion that if the environmental light exposure for humans could be manipulated, it would be possible to find a new way to influence food intake patterns as well as metabolism.

It is hoped that more research should be undertaken in order to identify the mechanisms of action which is associated with the relationship between light exposure, hunger and metabolism.

Journal reference: Cheung IN et al. 2014. Evening Blue-Enriched Light Exposure Increases Hunger and Alters Metabolism in Normal Weight Adults. Sleep, vol. 37, abstract supplement, paper # 0114, p. A42