Using light to lose weight

Kathleen Blanchard's picture
Bright light could contribute to weight gain and more eating

Is it possible to manipulate light to stay healthier? That's the suggestion from a new study from Northwestern University researchers. Bright light in the morning and evening could lead to problems including blood sugar spikes and insulin resistance that leads to weight gain.

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Perhaps there is more to pulling the blinds at night so we don't wake up to sunshine and dimming the lights at mealtime. The Northwestern Medicine Study found bright lights increase insulin resistance that can lead to weight gain; particularly in the morning and evening.

Bright light spikes blood sugar levels

Previous studies showed constant exposure to bright light caused mice to gain weight. The scientists also noted from past research that people exposed to bright light after 12 pm tend to be thinner than those exposed in the morning.

When they looked at why it happens they found out bright light increases insulin resistance and raises blood sugar levels in the evening, which can eventually lead more insulin resistance and diabetes.

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Dimming the lights at night has also been suggested for a good night's sleep. Lack of sleep is also a trigger for weight gain.

The finding adds to growing evidence that lighting has an impact on our health, especially over time; in particular our weight and food intake.

Mice subjected to constant light eat more, even during normal rest periods.

"Future exploration should also investigate how the relative increase in insulin resistance with light exposure would be beneficial to weight regulation in the morning and detrimental in the evening, as suggested by earlier studies," the authors write.

Based on the finding, avoiding bright light in the morning and evening could help with weight loss and affect metabolism to keep us healthier.

Citation:
Cheung IN, Zee PC, Shalman D, Malkani RG, Kang J, Reid KJ (2016)
"Morning and Evening Blue-Enriched Light Exposure Alters Metabolic Function in Normal Weight Adults"
PLoS ONE 11(5): e0155601. doi:10.1371/journal.pone.0155601

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