Just as nature sheds a layer of snow, exposing the first blades of grass to the sun, so do we shed a layer of clothes in the spring. And expose the extra pounds we put on during winter. It’s an almost universal phenomenon – most people finish the cold months with a bit of extra padding here and there.
The reasons for this winter weight gain seem logical – we move less, we sleep more, and we indulge in tasty dishes and desserts without counting the calories. But even those who keep a strict diet will likely find that it’s harder to lose fat in winter. And it’s our body to blame for it.
Hormones work differently in winter
Melatonin is a hormone that regulates the day-night cycle in animals – and humans. Its levels in the blood influence our sleep patterns. Babies have higher melatonin levels than teenagers, so they sleep more. Teens have less, but the peak levels are reached later in the day. This is why teenagers like to stay up until late and sleep until noon. As we get older, our melatonin levels decrease – this is why the elderly usually require less sleep.
The production of melatonin is triggered by darkness – when it’s time to sleep. And, since days are shorter in winter, our melatonin production increases. Which means that we “hibernate”, move less and sit more. And in some people melatonin also has an effect on their appetite, making them want to eat more.
Vitamin D production is lower in winter
Vitamin D is a very useful substance, with an important role in bone and skin health. But it also helps our bodies break down fat. According to a 2010 study, a higher vitamin D and calcium intake can help with diet-related fat loss. But, as our body produces less of it in the winter, which decreases the efficiency of most diets.
Cold weather is also a factor
Our body burns more calories when it’s cold, as it needs more energy to keep us warm. But it wants to compensate this overconsumption of energy, which translates to a higher appetite. This has been imprinted in our brain over the thousands of years of our evolution, which means that cold will always make us hungry.
Can’t put all the blame on winter
While it’s normal to gain weight in winter, we can’t put it all on our metabolism. The holidays filled with desserts, our own reluctance to get out of the couch are also to blame. Let’s face it: we are lazier in winter. And this usually translates into some extra padding gathered on our belly.