Warmer Temperatures, Bigger Bodies?
Can turning up the thermostat be making us put on weight? A recent review article1, suggests that it just might. Thanks to thermostats and indoor heating, we’ve reduced our exposure to the cold, which means that we may be relying less on our body’s natural mechanisms to keep us warm – mechanisms that would normally burn calories.
In the article published last week in Obesity Reviews, the scientists noted that the indoor temperatures at which we feel comfortable have nudged upwards over the last 30 years or so. On top of that, we’re moving in the direction of what’s known as ‘thermal monotony’ – we tend to keep indoor temperatures fairly steady at all hours, rather than letting them dip at night as they would naturally do. Not only have we increased our average living room temperatures by a couple of degrees, but our average bedroom temperatures at night have bumped up even more.
The review zeroed in on the role of a particular type of fat, called brown fat, that has been known to play a major role in generating heat – at least in small animals and babies. As people get older, they tend to lose their brown fat, accumulating instead the ‘white’ fat that serves primarily as a holding tank for extra calories. Until recently, the assumption has been that adults have little to no brown fat – and that even in those who do, it doesn’t do very much in the way of burning and producing heat.
But recent technological advances have allowed researchers to more readily identify brown fat deposits in adults. In one study cited in the review, metabolically active brown fat was detected in 23 of 24 subjects when the ambient temperature was dropped by about 6 °C (11°F). A little calculating suggested that -under conditions where the brown fat could be fully activated – subjects could burn the calorie equivalent of about 4 kg (almost 9 pounds) of body fat in a year’s time.
Keep in mind, though, that not all adults have brown fat, and it’s not easy to determine if you do or you don’t (a PET scan under cold conditions is required). And, unlike animals that naturally eat less as it gets hot and move around when more it’s cold, we don’t shift our food intake and energy expenditure when temperatures rise and fall. Overcoming our natural inclinations, we’re perfectly happy to sit in our heated homes and chow down in comfort.
So while it’s tempting to think that ‘chilling out’ might be the answer to losing weight, a healthy diet and plenty of exercise is still in order. While it may play a role, simply turning down the heat and shedding some clothes isn’t going to solve the problem on its own.
1Johnson F et al. Could increased time spent in a thermal comfort zone contribute to population increases in obesity? Obesity Reviews, 2011 (published online 1/24/2011)
Written by Susan Bowerman, MS, RD, CSSD. Susan is a paid consultant for Herbalife.
Tags: brown adipose tissue, brown fat, brown fat white fat, burn calories, burning calories, herbalife, how do you burn calories, metabolism, weight maintenance
Interesting! Thanks for the post
Thank you very much for this informative blog. It would be cool to have some Rss feed subscription here.
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I have read that our appetites increase with colder temperatures. Also, many people exercise less with colder temperatures, as do some mammals and other animals. Also, people in warm climates are often thinner. So I have my doubts about the analysis but I support your conclusion.
Hi Rick-
Thank you for your comment. Our appetites do tend to increase in colder temperatures – we’re biologically programmed to take in more calories during colder times of the year to help keep up the body temperature. And that would be a good thing if we were living outdoors and needed the extra calories to help us stay warm. But since most of us live in temperature-controlled environments, the body doesn’t use up the extra calories to generate its own heat. But that doesn’t mean, conversely, that when the weather warms up (or when we turn up the thermostat) that we eat less. There are just too many factors at work in determining how much we eat, and when. This particular research study was pointing out that since we are living in a more temperature-constant environment, we may be less likely to activate the heat-generating brown fat that could possibly help us with weight maintenance.
I?ll right away grab your rss as I can’t to find your email subscription link or newsletter service. Do you’ve any? Kindly let me know in order that I may just subscribe. Thanks.
Hi-
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