Study: Blue light emitted by iPhones and iPads can make you fat

“Using a computer or smartphone at night can cause us to pile on the pounds, new research has revealed. The study found a link between blue light exposure – blue light is emitted by smartphones and tablets – and increased hunger,” Emma Innes reports for The Mail. “It found that exposure to the light increases hunger levels for several hours and even increases hunger levels after eating a meal.”

“Results of the US study show that blue-enriched light exposure, compared with dim light exposure, was associated with an increase in hunger that began 15 minutes after light onset and was still present almost two hours after the meal,” Innes reports. “Blue light exposure has also already been shown to decreased sleepiness in the evening increasing the risk of insomnia.”

“Study co-author Ivy Cheung, of Northwestern University, in Chicago, said: ‘A single three-hour exposure to blue-enriched light in the evening acutely impacted hunger and glucose metabolism. These results are important because they suggest that manipulating environmental light exposure for humans may represent a novel approach of influencing food intake patterns and metabolism,'” Innes reports. “The findings are published in the science journal Sleep and were presented today at an annual meeting of the Associated Professional Sleep Societies in Minneapolis.”

Read more in the full article here.

MacDailyNews Take: The study group comprised 10 healthy adults over a 4-day period.

A more comprehensive study is absurdly easy to imagine.


  1. So at least some of the 10 people got hungry while being exposed to blue light from 15 minutes to two hours after eating?

    So don’t sit in the dark using your iPhone. There, problem solved.

    1. Good point. F.lux is very good, although it conflicts with similar applications and ColorSync profiles.

      SO! If you’re paranoid about blue lights making you FAT, or you just have a penchant for believing every bad science article foisted into the public eye, GO GET F.lux! Highly recommended.

  2. The problem is a lot worse than that. phones and iPads are just part of the problem. EMFS are producing radiation fallout that are producing free radicals in the body. Worse place to be is in a metal tube 30,000 ft high. A 3 hour ride in a microwave oven. Drink plant of water. See Dr. Jack Kruse.

  3. I wonder if red light exposure causes a decrease in appetite. Red is on the opposite side of the light spectrum from blue. I also wonder if the size of the wavelength is the cause. If the wavelength is shorter it might contain more energy. This energy could speed up the biological processes and cause one to be hungrier. So, a longer wavelength exposure like to infrared would slow the biology and cause a decrease in appetite.

  4. Before we begin making public health policy changes and regulations based on this, let us wait for a proper study.

    That said, it is quite possible that this can be true (even with the minuscule sample they had here). If that is the case, more research should be done to detect if warmer light (orange) has opposite (or neutral) effect on appetite. It should be a big challenge to develop LED lighting that has warmer colour temperature.

    1. Actually, even a cursory google search turns up enough studies to make you fat trying to read them all. While the background question isn’t new, the transport medium is.

      And if you read the article it doesn’t single out Apple products, that’s just the headline to lure you in and start raving…

        1. Which part bothers you? The apple headline from MDN? I don’t care for it much but it did get me to read the story.

          Or that exposure to excessive blue light can alter your metabolism?

            1. No-one likes your “crusty old jerk” comments, botvijerk.
              How about you try to not insult anyone for a whole day.
              Then, maybe, for a whole week.
              Then, who the heck knows what might be possible?

    2. There have been design studies from many years back that showed painting the interior of Restaurant’s red makes people more hungry. So this blue puzzles me.

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