It is the middle of July and there is a cold wind blowing outside. It was dark when you got home from work. It is an hour before bed-time and dinner is a distant memory now. You are curled up on the couch with a good movie and a nice bowl of… fruit salad? Not likely!
Winter is the season for mugs of hot chocolate with marshmallows, bowls of warm soup, and big chunky chocolate-chip cookies. With our winter appetites it is no wonder that some surveys show that people gain an average of two kilogrammes in the cold season. In this article we look at some reasons for why we eat as we do in winter.
Selling like Hotcakes
According to a study published by the University of Massachusetts Medical School, people tend to naturally seek out and eat higher calorie foods in winter for biological reasons. The study showed that people consumed an average of almost 100 more calories each day in winter than they do in summer.
They say that this could be because our primitive instincts urge us to find food quickly and eat it fast in winter, which is usually the most difficult season to survive as an animal. Even in relatively modern times, in the days before global supply chains, freezers, preservatives, greenhouses, and insulated animal shelters food options in winter shrank as the cold, dark months dragged on.
It seems to make sense that, if our bodies are programmed to believe that winter is a time of food scarcity, we will feel the urge to impulsively eat any rich food we happen to see in the course of our day. This might explain the phrase “selling like hotcakes” because anyone with a stall selling hot, calorie-rich food on a cold day is sure to do good business for as long as the customers can’t feel their finger-tips.
Could it be SAD?
Unfortunately, a small number of people suffer from SAD during the winter. SAD is the acronym for Seasonal Affective Disorder, a recognised category of depression which is thought to be cause by the sufferer not getting enough sunlight. Sunlight is pretty much essential for normal bodily functions like the circadian rhythm which most people know as their internal body clock.
A lack of enough sunlight can cause a significant reduction in the amount of serotonin in the blood. Serotonin is an important hormone which works on the brain to lift one’s mood, so if you do not have enough of it depression could set in. Some people overeat when they are depressed, because high-calorie foods cause the body to make more serotonin.
In other words, if you can’t get your serotonin from the sun, you might find yourself trying to get it from custard slices and hot fudge pudding.
Baby, its cold outside
Like the song says, I really must go, but its cold outside… There is no question that we stay indoors when it is cold outside. Compare your local neighbourhood playground in summer after school to what it looks like now to understand how our habits change in the winter. If you are not outdoors, pushing the kids on the swing you are probably indoors watching TV instead.
If you work in an office, you will be less interested in walking through winter rain to the new café around the block when you can eat your lunch in the building cafeteria instead. All of these small adjustments to our lifestyle affect our overall activity levels, thereby lowering our Basal Metabolic Rate (BMR) which ultimately determines how many calories we use in the long run.
Paired with a lowering of activity, when we stay indoors we are more tempted to eat and drink sugary things because they are just an arms-length away from us. Using less calories than usual whilst consuming the same (or more) calories as usual is a true and trusted formula for weight gain.
Another hormone!
There could be another hormone involved in our winter cravings: melatonin. Melatonin causes sleepiness and is released into the bloodstream when it gets dark. In addition to causing sleepiness, it works on a number of different body organs and has a recognised effect on appetite.
Scientists are still studying melatonin and trying to understand everything that it does for humans, because it seems to have different and sometimes opposite effects on different animals and plants. What we do know is that we have more of it in winter because there is less sunlight (that is why it is harder to get out of bed on a winter morning), and it affects our appetite in some way.
Clearing up a myth
You do not eat lots in winter to stay warm. Your body core stays at the same temperature in winter and summer, irrespective of whether you are feeling hot or cold. In modern Australia we move from one heated building, to a heated car or train or bus, to another heated building in winter.
When we work or play outdoors we wrap up snugly so that the outside temperature does not get to our core. This means that our bodies require a very small amount of extra energy to maintain our normal temperature. It is true that people with large fat stores around the body are better insulated against extreme and sustained cold, but the practical difference is meaningless from a survival aspect so there is little reason to believe that we are genetically programmed to eat more so that we can get fat in order to stay warm in winter.
What to do about it?
So now that we have established that winter is different from summer and that there are things going on in our bodies that we cannot fully control, what can we do about winter weight gain? Our top three tips:
Don’t stress over it. It is perfectly natural and normal to have some weight gain over winter. There isn’t an animal or person on this planet that does not have weight fluctuations over time. This does not mean that it is okay to have massive weight swings, but a one or two kilogramme variation over the course of a year is nothing to worry about. If you worry too much about gaining weight over the winter, you could set off a cycle of unhealthy behaviours which could make things worse. Remember that your mental wellbeing is the ultimate key to long-term weight management.
Exercise. You can counter-act many of the weight-gain factors of winter by exercising regularly, especially if it gets you out of the house and into the sun. If it is too cold to go for a brisk walk or steady jog, then try skipping, aerobics, yoga, or something similar in a sunny room. Gym classes are a great option in winter because of the group dynamic and the fixed schedule of being out of the house. Read what we have written about the benefits of exercise for your brain to see how it can counteract the hormonal changes caused by winter.
Be aware of the winter effect. Knowledge is power, as the saying goes. When you know that your winter morning sleepiness is caused by increased melatonin, you will want to fight it and get out of bed with purpose. When you know that a lack of sunlight is draining your energy levels, you will try to get some rays whenever you can. If you know that you don’t need to eat extra to stay warm, you might lay off the bread and butter pudding. Just being mindful of how your habits and lifestyle change in winter can be enough to change them for the better
