Is Global Warming Making You Fat?

It sounds preposterous, and clearly global warming won’t make it more difficult to fit into your clothes tomorrow morning, but there may be a subtle influence that global warming could have on your weight.

White fat is the stuff you don’t want if you’re trying to lose weight. It’s stored energy but since most of us have plenty of food to eat it’s unlikely that you’ll go hungry and need to draw on your white fat reserves. Unless you restrict your eating and ramp up your physical activities you’re stuck with the fat you don’t want in your midsection, butt, thighs or elsewhere on your body.

Unlike white fat, brown fat is a good fat because it may help with regulating your weight. Brown fat doesn’t just sit under your skin waiting for you to starve. Brown fat is brown because it has lots of mitochondria that generate heat by burning fat and glucose. It also can suck up glucose to help control diabetes.

When you were born you had deposits of brown fat that generated heat, This helped you adjust to the colder temperature outside of your mother’s womb. It was thought that we lost brown fat as we matured since we could keep warm by putting on clothing or turning up the thermostat but recent evidence suggests that many of us retain some brown fat into adulthood.

Researchers in the Netherlands looked at data from the Centers for Disease Control and Prevention (CDC) on diabetes incidence between 1996 and 2009 and compared it with mean annual temperature readings. They also looked at World Health Organization data on the prevalence of obesity in 190 countries in 2014 and the average annual temperature for those countries in the same year. They controlled for sex, age, and income levels and found that diabetes increased by 0.3 per 1,000 for every increase of 1-degree centigrade (33.8 degrees Fahrenheit) and incidence of obesity increased by 0.29 for every 1-degree centigrade increase in temperature.

While these findings don’t conclusively demonstrate that global warming causes obesity or diabetes, it’s likely that with the average temperature rising, there’s less need for our brown fat to generate heat to keep us warm. As a result, the energy that’s no longer being used by brown fat to keep us warm is instead being stored as white fat. So, in addition to raising the sea level, global warming may be raising our fat level.