A new study offers us a surprising answer to why when we are on vacation we tend to gain more weight than we want. While it is true that during the Christmas holidays we are more exposed to delicious foods than the rest of the year, some studies have shown that in winter, we continue to accumulate kilos despite conscious efforts to lose them. Why?
Work by researchers at the University of Alberta in Edmonton (Canada) reveals an unexpected culprit for winter weight gain: the absence of sunlight.
The researchers, led by Peter Light of the Alberta Diabetes Institute, examined the effect of sunlight on subcutaneous fat cells, or white fat cells just under the skin. The results of the study have been published in the journal Scientific Reports.
Sunlight ‘burns’ fat
Light and his team examined so-called subcutaneous white adipose tissue , which, as the authors explain, is the “largest fat depot in humans and a central player in the regulation of whole body metabolism.”
White fat is known as “bad” fat because it stores calories that are ideally burned for energy. If dysfunctional, this type of fat can lead to cardiometabolic disorders such as obesity, diabetes, and heart disease.
Thus, in an attempt to help people with type 1 diabetes, experts were working on a way to genetically manipulate these white fat cells to produce insulin when exposed to light. They accidentally discovered that these cells tend to shrink under the effect of so-called blue light from the sun, that is, the visible type of light that increases attention and mood during the day.
To further test their discovery, the scientists took samples of these cells from patients undergoing weight loss surgery and examined the effect of blue sunlight on fat cells.
Here’s what they found: “When the wavelengths of blue light from the sun – the light we can see with our eyes – penetrate our skin and reach the fat cells just below, the lipid droplets decrease in size and become they release from the cell. In other words, our cells don’t store as much fat, “clarifies Peter Light.
“If we turn our findings around, insufficient exposure to sunlight during winter (and even more so in areas far north) can promote fat storage and contribute to the typical weight gain that some of us have during winter. winter, “says Light.
According to Light, it is not surprising that if light regulates our circadian rhythm, it could have the same impact through fat cells near the skin.
The findings may pave the way for new weight loss strategies or light-based therapies in the treatment of obesity and diabetes.
However, the scientist cautions against taking these findings literally and looking for exposure to sunlight to lose weight, as there are still many variables that remain unknown, such as the intensity and duration of light necessary for it to occur. activate this way.
Reference: Subcutaneous white adipocytes express a light sensitive signaling pathway mediated via a melanopsin / TRPC channel axis. Nature 2017. doi: 10.1038 / s41598-017-16689-4
