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Cold Exposure Builds Brown Fat... & Fools Your Body Fat Scanner

Updated: 5 days ago

I was a fat kid, who grew up to be a pudgy young man, who matured into an obese, middle-aged adult Dad. By mid-40’s, I was setting a bad example for my kids, my wife was unhappy, and I was embarrassed by the shape I was in. This is my story.

When I decided to do something about it, I started skipping lunches and experimenting with different exercise classes. I tried yoga, spin, kickboxing, and weight training. My favorite was a cardio ballet class.

I stuck with the fasting and I quit alcohol and I increased my caffeine intake about 3-fold.

I dropped to 185 lb.

My wife was buying my clothes at Goodwill. She’d take them back after a few weeks and buy me smaller clothes, because I was shrinking so fast. My waist went from 44 to 34 inches.

That was over three years ago and I’ve mostly kept the weight off, although the shirts I bought when I was 185 lb don’t fit me now that I’m back up to 204.

Because my son has been Type 1 diabetic since he was six years old, I’d already learned a few things about the Atkin’s diet, low carb diets, blood glucose levels, insulin, and ketosis. So I eliminated carbs, took some of my son’s keto strips and started running my metabolism in and out of ketosis.

As part of my journey, I’ve learned that most of what I thought I knew about diet, health, nutrition, metabolism, and weight loss is plain wrong.

To learn what worked for me, I had to read things that didn’t come from official or popular sources, and run my own experiments on myself. One of the most important books was Scott Carney’s What Doesn’t Kill Us, which described the incredible health benefits of hyper ventilation and immersion in freezing cold water.

Carney's book chronicles his own journey towards fitness under the tutelage of the brilliant Dutch eccentric Wim Hof, who pioneered cold immersion practice and revealed the benefits of maintaining brown fat. (The medical term is called brown adipose tissue.)

Most of the fat in our body is in the form of white fat, which is a store of energy. But brown fat is different from white, because brown fat contains extra mitochondria for thermogenesis (generating heat to keeping our body warm). In other words, when you build brown fat, it is easier to boost your metabolism to burn off white fat.

Although all human babies are born with brown fat, most people lose almost all of it by the time they reach adulthood. Only regular cold exposure will cause our bodies to build brown fat.

The thing about immersing yourself in 32F water is that it hurts. It’s painful.

To withstand that, you have to gain control of your own nervous system, because every fiber of your body is in a state of panic. Staying in the ice water requires a meditative control of that panic.

I’ve been doing the ice baths for close to a year now. I can bathe in 45F water indefinitely — at least up to 15 minutes, after which I get bored. And I’m doing 32F for 3–5 minutes (which is tough).

I get cold, but I don’t even shiver anymore.

According to the theory of cold immersion response, I don’t have to shiver anymore, because my body has enough brown fat, to withstand prolonged exposure to cold temperatures, including freezing water.

beautiful, refrigerated baths.

Since learning about and practicing ice baths I’ve been feeling better than I ever have.

There’s just one problem…

Although I was feeling better, the body fat measurements I was doing at the gym showed me getting fatter and fatter. According to my trainer, I was ballooning from 19% to 23% total body fat, and on the verge of medical obesity, even though I wasn’t gaining weight.

If they are accurate, then I’d better make some changes fast, because an extrapolation of my trendline means that I’m just another 6 weeks away from crossing the 25% body fat threshold that defines obesity.

But what if these results are inaccurate?

Cold water immersion has added brown fat to my body, and maybe electronic body composition meters do not measure brown fat accurately.

The machine used at my gym uses bioelectrical impedance analysis to measure “adiposity.” That is, it runs an electrical current through my body. My bare feet stand on electrodes, and I grip additional electrodes with my hands. While the measurements are being recorded, I can feel the tingle of electricity going through my feet and fingers.

The machine is calibrated to calculate my body fat percentage based on the changes in electrical impedance in my body. That is, muscle, water, bone, and fat all have different electrical conductivities. By varying the voltages, measuring the changes in current, and accounting for my height, weight, and age, the machine can correlate electrical impedance with body fat percentage.

Because most people have only a minimal amount of brown fat, the distribution of fat between white, brown (and beige) need not factor into the calculations. But what if the impedance of brown and white fat were different and this was causing erroneous estimates of my body fat composition? Well, it might cause me to do some things that are probably good for me anyway, like increase my exercise and reduce my calorie intake from carbs. But it sure wouldn’t do much for my sense of making progress.

Every time I get my body composition results, I feel like the fat little kid that lost every foot race and damn near failed every middle school gym class.

I must clarify that my expensive gym in the suburbs of a major American city relies on a business model that enhances and exploits insecurities in people like me.

So I’ve fired my trainer and cancelled my subscription. 

I’ll figure something else out.

When you want to learn more about the multiple benefits of cold water immersion, watch this TEDx talk by investigative journalists Scott Carney in which he explains how far we’ve strayed from the environmental stressors that keep our bodies strong.


About the Author

Thomas P Seager, PhD is an Associate Professor in the School of Sustainable Engineering at Arizona State University. Seager co-founded the Morozko Forge ice bath company and is an expert in the use of ice baths for building metabolic and psychological resilience.

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