Obesity in children: Caused by pregnant mom’s sun deprivation? By Marc Sorenson, EdD. 
Obesity in children is linked closely to maternal vitamin D status in pregnancy.[1] And is anyone surprised about this? First of all, everyone should know that vitamin D deficiency is caused by inadequate sun exposure. So, if high vitamin D is associated with less weight, it is because of high sun exposure. That is of course, unless the research involves vitamin D supplementation. Because sunlight produces nitric oxide, endorphin, serotonin, dopamine and other chemicals, only research can determine if vitamin D is protective. Therefore, a supplementation study would be required.
What did the research show regarding obesity?
It seems like sun exposure, which produces all of the photoproducts, would always be the best way to prevent weight gain. Most noteworthy, however, is that we are discussing only the sun deprivation aspects of obesity. That is because being overweight is primarily due to 1. eating junk food and 2. not staying active. This blog, however, deals only with extra weight due to sun deprivation.
So what did this obesity study show? To perform the research, pregnant women were first of all measured for vitamin D levels before birth. In addition, their newborns were followed for 4-6 years and then compared for obesity levels. In conclusion, those whose mothers had the lowest vitamin D levels had children with the greatest obesity problems.
So, we still don’t know if vitamin D was the protective photoproduct against obesity in children. Because of that lack of surety, let’s visit some research on sunlight and obesity.
In addition to the aforementioned research, another scientific paper “sheds more light” on the subject of obesity.[2]
This research was conducted on mice with shaved backs, because the applied light needed to be unimpeded by hair. Also, a second part of the experiment was to put them on a high-fat diet. Finally, they were exposed to non-burning ultraviolet radiation (UVR) during a three-month period. (UVR is the same light they would receive from sunlight). The mice, because of the high-fat diet, would have been expected to gain weight rapidly. But with UVR, the weight gain was consequently (and impressively) reduced. As a result of the treatment the mice achieved 30-40% less weight gain. That is, compared to the expected weight gain.
Blue light for reduced obesity?
Furthermore, a study published in 2017 showed that the blue-light spectrum of sunlight can cause subcutaneous fat to decrease.[3] In other words, it can cause obesity to diminish, much as good nutrition would also cause it to decrease. Thus, the action of sunlight may help one to prevent obesity or even to create slimness. Consequently, blue light from the sun may be a preventer of obesity, and an adjunct to good nutrition and exercise.
Is obesity reduced by morning light?
So—here we have another benefit of sun exposure—morning sun specifically! A recent study from Northwestern Medicine demonstrates that timing and intensity of light correlate with body mass index (BMI).[4] So to understand the research we need to understand BMI. BMI is a numerical computation comparing height and weight. And it is a commonly used method to assess obesity or the lack thereof. So a high BMI usually means a person is obese or at least approaching obesity. Optimal BMI is 18-25. Below 18 is considered underweight, above 25 is overweight, 30 is obese and 40 and above is morbidly obese.
So does sun exposure influence BMI? Is obesity reduced?
This study showed, first of all, that exposure to bright morning light was directly related to BMI. After adjusting for confounders, it was determined that very early exposure to morning light correlated remarkably to lower BMI. Opposite to what one might expect, when light intensity was equal at different times of the day, results were identical. Consequently, those who received the earliest bright light had lower BMI. Furthermore, for each hour later in the day when light exposure occurred, BMI increased by 1.3 units. This fact is exceptionally important, since a person who has a BMI of 25 (upper ideal range) could approach 30 (obesity). And that would be due to the habit of later sun exposure (10:00 AM rather than 6:00 AM).
Does vitamin D supplementation help prevent obesity?
Another scientific paper “sheds more light” on the subject of obesity.[5] This research was conducted on mice with shaved backs that were placed on a high-fat diet and then exposed to non-burning ultraviolet radiation (UVR) during a three-month experiment. The mice, without the benefit of UVR, would have been expected to gain weight rapidly on that diet, but when they were exposed to UVR, the weight gain was impressively reduced. The UVR treatment achieved a 30-40% reduction in weight gain, compared to the expected weight gain with the high-fat diet.
Interestingly, when vitamin D supplementation was used, it did not help, and actually stopped the positive effects of UVR treatment.
In conclusion, the pandemic of obesity may be exacerbated by sun deprivation. And, it may be due to something other than low vitamin D. Expectant mothers and their children should always obtain plenty of non-burning sun exposure. So should most other members of the human race. Happy sunning! 
Also see: http://sunlightinstitute.org/sun-exposure-reduces-obesity-vitamin-d-not
Read My book, Embrace the Sun, available at
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[1] V. Daraki T. Roumeliotaki G. Chalkiadaki M. Katrinaki M. Karachaliou V. Leventakou M. Vafeiadi K. Sarri M. Vassilaki S. Papavasiliou M. Kogevinas L. Chatzi. Low maternal vitamin D status in pregnancy increases the risk of childhood obesity
[2] Geldenhuys S, Hart PH, Endersby R, Jacoby P, Feelisch M, Weller RB, Matthews V, Gorman S. Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet. Diabetes. 2014 Nov;63(11):3759-69
[3] Ondrusova K, Fatehi M, Barr A, Czarnecka Z, Long W, K Suzuki K, Campbell S, Philippaert K, Hubert M, Tredget E, Kwan P, Touret N, M Wabitsch M, Lee K, Peter E. Light P. Subcutaneous white adipocytes express a light sensitive signaling pathway mediated via a melanopsin/TRPC channel axis. Scientific Reports 2017 November 27;7:16332
[4] Reid KJ, Santostasi G, Baron KG, Wilson J, Kang J, Zee PC. Timing and intensity of light correlate with body weight in adults. PLoS One 2014;2;9(4)
[5] Geldenhuys S, Hart PH, Endersby R, Jacoby P, Feelisch M, Weller RB, Matthews V, Gorman S. Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet. Diabetes. 2014 Nov;63(11):3759-69