Can central heating make you fat?
A paper published in the British journal Obesity Reviews has backed up a hypothesis that warm indoor temperatures in winter can be a significant contributor to obesity. Researchers found that since central heat became common in Britain and the US, the average temperature of rooms has climbed steadily. This, they say, correlates with an increase in obesity.
In Britain, once infamous for the chilliness of what passed for “room temperature,” the average temperature of living rooms rose from an average 65°F in the late 1970s to 70.3° by 1996, the last year for which data was available. Bedrooms, which averaged 59° in 1978, reached 65.3° by 1996.
In the US, living rooms have been heated to a comparatively toasty 70° for decades, but the average bedroom has risen from 66.7° in the mid-80s to 68° by 2006. This, say the scientists, means that people no longer have to adjust to sharp changes in temperature indoors.
Even a relatively small temperature range from the lower 60s to the 70s meant that people exhibited a condition called “non-shivering thermogenesis,” which caused the burning of so-called “brown fat.” Unlike regular fat, brown fat is dedicated specifically to temperature regulation. When temperatures stay moderate in all rooms, the thermogenesis effect is not induced, and people accumulate brown fat.
The researchers emphasized that other factors such as poor eating habits and lack of exercise are also contributors to the increase in obesity, but that simply sitting in a 60° room can cause the body to use an extra 100–200 calories per day.