Blue light can better satisfy hunger pangs

If you have earned an evening dinner with your girlfriend today, ensure the surroundings are lit in blue - to give both of you a fulfilling eating-together experience.

According to new research, blue-enriched light exposure immediately before and during the evening meal may increase hunger and alter the metabolism.

"It was very interesting to observe that a single three-hour exposure to blue-enriched light in the evening acutely impacted hunger and glucose metabolism," said Ivy Cheung, doctoral candidate, interdepartmental neuroscience programme at Chicago's Northwestern University.

Results show that blue-enriched light exposure, compared to dim light exposure, was associated with an increase in hunger that began 15 minutes after the light's onset and was still present almost two hours after the meal.

Blue light exposure also decreased sleepiness and resulted in higher measures of insulin resistance.

During the study, 10 participants with regular sleep and eating schedules received identical carbohydrate-rich meals.

They completed a four-day protocol under dim light conditions.

On day three, they were exposed to three hours of blue-enriched light and the effects were compared with dim light exposure on day two.

"Manipulating environmental light exposure for humans may represent a novel approach of influencing food intake patterns and metabolism," Cheung said.

The study was published in the journal Sleep.