Need to be cool to be thin?

February 10, 2014

Are warmer homes, schools and work places contributing to the obesity crisis?

A new study from scientists at the National Institutes of Health has found that placing volunteers in temperatures of less than 59F (15C) for around 10-15 minutes caused hormonal changes equivalent to an hour of moderate exercise.

These same hormonal changes have been linked to the creation of brown fat, a form of fat that actually burns up energy.

Brown fat was once only thought to be found in babies, but scientists have since discovered that adults possess small amounts of the tissue, with slimmer people having more.

Around 1.7 ounces of brown fat are capable of burning up 300 calories in a day – the same amount of energy stored in 1.7 ounces of white fat – the tissue where excess calories are stored.

The new research has now added to a growing body of evidence that exposure to cold temperatures can help people to control their weight.

Dr Paul Lee, who led the study and is now based at the Garvan Instutite of Medical Research in Sydney, found that exposure to the cold resulted in the release of two hormones called irisin and FGF21 that are known to transform white fat into brown fat. . .

The researchers from the Maastricht University warned that modern life meant people spent most of their lives exposed to warm indoor temperatures and so our bodies are not working as hard to stay warm.

They said the tendency for offices and homes to be temperature controlled in the winter could be contributing to the obesity crisis.

Marken Lichtenbelt, the lead author of the paper, said: “Indoor temperature in most buildings is regulated to minimise the percentage of people dissatisfied.

“This results in relatively high indoor temperatures in wintertime. This is evident in offices, in dwellings and is most pronounced in care centres and hospitals.

“By lack of exposure to a varied ambient temperature, whole populations may be prone to develop diseases like obesity. In addition, people become vulnerable to sudden changes in ambient temperature.”

Temperatures which were considered normal for homes, schools and work places a few decades ago are regarded as unhealthily cold now and linked to diseases of poverty like rheumatic fever.

But this research suggests that the warmer temperatures prescribed for healthier homes and work places while helping health in one way are contributing to problems in another.

These findings suggest we’re fatter because we’re warmer and we need to be cooler to be thinner.

Could the obesity crisis be due not just to too much sugar, but too much heat?

Hat tip: Tim Worstall


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