Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
31 Jan

Is Central Heating Related to Obesity?

thermostatWhy are so many people in first-world countries so overweight? Why is metabolic syndrome so prevalent? The familiar contenders are diet and exercise – more specifically, the wrong kind of each. Both Conventional Wisdom types and nutrition nerds (myself included) agree that we’re doing something wrong in the kitchen and the gym, and that fixing that stuff could solve most of our weight (and even health) problems. Of course, that’s about all we agree on. Specific definitions of “fixing” and “that stuff” remain subjects of vociferous debate. That said, I like when we can agree on something, even if that something is just speculation about another possible factor in the obesity problem. In today’s Monday Musings we’ll take a look at one such factor.

A recent study out of the journal Obesity Reviews notes that it’s not just diet and activity levels that have changed in correlation with rising obesity numbers, but ambient temperature. To be more specific, people are heating their homes at all hours of the day, even as they sleep, and spending less time outdoors exposed to the elements. Central heating is more common, while space heaters, fireplaces, and electric heaters are less common, meaning the entire house gets and stays warm. People in developed countries exist in relative thermoneutrality: a nice 68-72 degrees F. The authors guess that with less exposure to thermal stress, we’re burning fewer calories. Our bodies have an easier time regulating our internal temperatures, and expend less energy doing so.

On the surface, their ideas might remind you of the outdated, overly-simplistic calories in, calories out model, where people are fat because they eat a few extra candies between lunch and dinner that add a few dozen calories to their daily allotment. It’s more complex than that, though. Exposure to cold is a type of stressor; to be specific, it’s a thermal stressor. Our bodies respond to stressors by adapting and (hopefully) improving, as you well know, and hypothermal stressors, like taking a cold bath, going for a swim in the middle of winter, or even letting the heat go off at night, induce the creation of brown fat. Brown fat is different from the reviled and feared “white fat” in that it keeps us warm by burning white fat. Newborns have lots of brown fat because they can’t shiver, can’t crawl (away from cold and toward warmth), and have underdeveloped central nervous systems that can’t be counted on to react quickly enough to changes in ambient temperature. It’s how they stay warm. Adults have far less brown fat, but they can develop more through exposure to cold. Furthermore, brown fat levels in adult humans are highest during winter and linked with less visceral fat and a lower BMI. If you’re subjectively cold, chances are you’re spurring the creation of new brown fat or increasing the activity of already-present brown fat.

This all seems quite reasonable, doesn’t it? I do love it when I can agree with obesity researchers.

On a different note, a quick word about that Yahoo! Shine article floating around. You know, the one telling you the eight ways carbs will make you lose weight. It’s silly and not worth a lot of typing, so I’ll make it short. The thing that jumps out at me is the author’s obsession with “Resistant Starch.” First of all, I’m not sure why it deserves repeated capitalization (maybe it’s some sort of deity?), and second, resistant starch is just another type of prebiotic whose fermentation by microbiota releases beneficial short chain fatty acids. You can get the same kind of reaction by eating other sources of soluble fiber, many of them decidedly low-carb. Think leafy greens, broccoli, berries, apples, jicama, onions, garlic, leeks, Jerusalem artichokes. And yes, if your activity levels and metabolic health permit, Primal starches are good sources of resistant starch and soluble fiber alike, but it’s not the carbs doing it. It’s the “carbs” that you literally cannot digest without your little microscopic friends’ assistance.

Can keeping central heating on really be at least somewhat responsible for the obesity epidemic? Have you ever noticed a correlation between ambient temperature and your own weight? Let me know in the comment section!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Definitely a connection – I see it in myself and also in my dogs. I feed my dogs more in winter but they stay the same size and weight. That’s because they burn more calories simply staying warm.

    And you could have a whole other post on weight and remote controls! Same principle – we live in a society dedicated to making life easier and more comfortable and all the time we get fatter and fatter.

    Dawn wrote on February 3rd, 2011
  2. Interesting,Being from the NorthEast with Huge temp swings,I have found cold weather makes me put on a layer of fat. Disclaimer:Before everybody gets worked up I am a runner, 2:32:00 marathon 31:40 10 K, 5’9″ 160 pounds usually 8-10% Body fat. I was also a full time ski instructor at Killington for years. As a ski bum I ate very little,was sking 6 hours a day,then doing my 8-10 mile runs at night, Every winter I would put on a layer of fat that would disappear every spring as soon as it got warm, food intake did not vary much. I always attributed it to the body putting on a layer of insulation for the extreme cold(Vermont). I also remember a study that was done on elite swimmers in a pool where one study was done on training in a warm pool 70 deg.And the same swimmers in much cooler pool 50 deg. The period when swimming in the cooler pool reveiled higher fat levels retained over the same workouts and food intake.
    At a certain temp does the body actually go into a A”fat saving mode” to cope with cold weather? Onthe other side I am also aware of Polar expeditions where 5-6,000 calories a day are required to keep up with demand.
    Any Info on this?
    Many thanks!

    Shawn Whalen wrote on February 3rd, 2011
  3. While cold might stimulate the metabolism, it also certainly makes people hungrierrrrr. I’m not sure shivering away a few extra calories can make up for the non-Primal muffin that suddenly looks magically appetizing the moment the temp drops below a certain threshold….

    winter bear wrote on February 3rd, 2011
  4. Hello!

    This makes very interesting reading!

    I find that I put on weight during the winter months, and that I lose a lot of weight in the spring months (so March April and May). This stays the same level until around October.

    I have always thought this as due to my unwillingness to go outside and exercise and my willingness to cosy up under a duvet and hybernate. And then Spring arrives and I can’t get enough of the longer daylight hours.

    I suppose the lure of the artiical warmth can stop us from being active.

    Sophie L wrote on February 8th, 2011
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  6. I work in a factory. We make all sort of bedding.
    No retail. Just manufacture.
    Business has been in existance since 1959.
    I set the meter on 6, which correlates to about 70 degrees F. on a duvet and used vicuña and it is a better sleep. You guys are right about the temperature.

    Ross Wilkinson wrote on October 10th, 2011
  7. I have wondered about this for a long time, though I think it goes further than just modern heating systems, and also relates to modern cooling.

    The heating connection is obvious, and anyone who spends time outside year round will tell you that being out in the “cold” really wipes you out. Even before you get to the point of shivering, your body is using up more energy to keep itself warm. Scouts know this, which is why they try to serve good “hearty” meals on cold weather trips — some primal, and some not. Direct warming (from having something warm in your stomach) is only part of it.

    But what does modern air conditioning (primarily cooling) do for/to us? I know in my case it boosts appetite. All other things being equal, when I am hot, I am not as hungry. I remember plenty of times growing up (in a non-AC house) where by dinner time we were almost too hot to eat anything. Meals were “lighter”, and even so we didn’t eat very much.

    By keeping cool all the time, are we tricking our bodies into thinking that we are stuck in a perpetual “fall”? Is this triggering some kind of body response that suggests it is time to put on fat for the winter? It would be an interesting research area if someone could figure out how to measure it.

    I would argue that the American obesity trends correlate better with modern cooling than with modern heating. I am not discounting the contribution of diet, only suggesting that it is more complex than *just* what we eat.

    This is all the more reason to get outside, often, and to do it year round.

    BTW, I don’t see an area for “welcome” messages, so I will just add here that this is my first MDA post. I have been reading here for months, but I just made the plunge. I have been eating more primal for less than a week, but I am already feeling better and I have lost some initial pounds. “Water weight”? Probably, but it is an encouraging start.

    Philmont Scott wrote on December 16th, 2011
  8. I moved from TX to Michigan and this is my first winter ever to experience snow. Everyone says I am lucky bcs this is the warmest winter ever but it’s too cold for me. I have lost 10 lbs so I am now 109lbs. I hate the cold and was getting worried about my weight loss since I have been eating whatever I want. I met a friend here who moved from South America a few years ago during one of the worst winters in years and lost 30lbs. She said it only happened the 1st winter though and has gained it back. She was too happy to be worried about it but I have been worried. I go to school so I have no choice and just try to walk as fast as possible when outdoors.

    Nelsi wrote on February 28th, 2012
  9. i think it has to do with places being to cold, hot and vitamin d levels, and sunshine as i think summer and winter survival mechanism to decrease energy for self preservation during wintery conditions .
    the far south areas are really hot which causes ppl to stay inside most of the time with cool air, countries to the far north are really cold thus ppl stay inside for heat and are not exposed to much sun.
    places like america ppl make plenty of money to buy tech and entertain themsselves inside. ppl buy homes and stay inside to stay cool and warm and theres winter 1/2 the year . and lastly the middle east isnt exactly well developed with income and tech most ppl are usually strolling around as theres not much to do and theres plenty of sunshine.
    anyone else have a theory.

    Brian wrote on December 17th, 2012
  10. Interesting article. I might mention I grew up in Melbourne Australia for the first 42 years of my life. The aborigines say it has 6 seasons in that area of the world. We use to say all 4 seasons in one day. I LOVE THE COLD the more freezing the better. When winter temperatures were below freezing during the 60’s and 70’s, I would ride to school on my push bike in short pants and no jumper and short sleeved shirt and wonder why every one was saying it was cold. I use to sweat at that temperature or at least be very hot. I always drank hot drinks and ate heavy foods – Pies, chips, roasts; etc. Not many salads. I moved to Queensland at 42 and took about 7 years to climatize. Still not sure if I really have adjusted even after 12 years. Recently, I went to Melbourne to visit my daughter and got a bad bronchial flu after about 4 days of extreme cold weather. I did though enjoy the cold wind and rain and the freezing on my skin. I still did not wear any coat and went about in thongs, short pants and a short sleeved shirt for the time I was there just as I do every day in Queensland. Despite getting ill I still did not feel cold. I have found since being in Queensland I do little physical activity as its way too hot for me, hence I have piled on the weight because I am so hot and sweaty all the time. I have no energy and also no incentive to do anything of interest that is physical because I rent and have to move house so frequently. Additional I have now been diagnosed with sleep aponea which is a cause for – high blood pressure and AF ( heart flutter ) which all contributes to sweating and low resistance to heat as well as overweight. I have all these issues as well as a constant low energy level and need to sleep a lot. Additional to this I get gout which can be triggered by stress, related to dehydration and heat exposure. I don’t take drugs, I don’t smoke and I don’t drink alcohol and never have.
    I never had these issues diagnosed in Melbourne when I was younger, but have had them only show up in hotter weather as I have gotten older.

    Kimbal wrote on January 3rd, 2014

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