The Life and Times of Brown Fat


For many years, brown adipose tissue was thought to be the exclusive property of “babies, young children, and other small mammals,” and its purpose was believed to be warmth, to protect the little critters and promote their survival.

In 2009, brown fat was discovered to exist in adults. Aaron Cypress, M.D., lead author of the relevant study, expressed hope that learning more about it could lead to the development of drugs that would stimulate brown fat to perform more efficiently, burn more calories, and alleviate obesity.

For Health magazine, Anne Harding described adults with brown fat:

They were younger and leaner. People who were older, those who were obese, and those using heart drugs called beta blockers were less likely to have brown fat. Dr. Cypress and his team also found that people whose scans were done in the winter had the most brown fat, while those scanned in the summer had the least…

Despite this, Dr. Cypress expressed doubt that hanging out in the cold would be an effective way to fight obesity. In the same year, Kathleen Doheny brought readers up to date:

Brown fat is now thought to be more like muscle than like white fat. When activated, brown fat burns white fat. Although leaner adults have more brown fat than heavier people, even their brown fat cells are greatly outnumbered by white fat cells.

Doheny learned from Dr. Cypress that a 150-pound human, for instance, might have 20 or 30 total pounds of fat, but only two or maybe three ounces are brown fat. However, that small amount, if correctly addressed, is capable of putting out enough energy to burn a pound per week off the body.

A couple of years later, Dr, Cypress spoke with International Business Times about the fact that brown fat plays a key role in pediatric metabolism and rhetorically asked what he called the billion-dollar question: Do children have more brown fat because they are thin, or are they thin because they have more brown fat?

By 2013, thanks to researchers at the University of Gothenburg, the word was out that brown fat tissue is associated with a reduced type 2 diabetes risk. This raised the stakes. Imagine if science could figure out how to both prevent a serious metabolic disease, and help people fit into their favorite jeans.

Then, things got even weirder with the discovery of beige fat, which is basically white fat (residing in the belly and thighs) that has been nudged by the brown fat into immolating itself. What can make this happen? Exposure to cold. But, as the Endocrine Society has found and reported, obese people by definition have systemic inflammation, and inflammation can obstruct the efforts of brown fat to change white fat into beige fat.

This connects to a recent Childhood Obesity News post about fat freezing, which mentioned that the application of extreme cold seems to work for some patients, on very small stubborn pockets of body fat, but is definitely not the answer for the overweight or obese individual.

Your responses and feedback are welcome!

Source: “Discovery of Cold-Activated Brown Fat May Lead to New Obesity Treatments,”, 04/08/09
Source: “The Truth About Fat,”, 07/13/09
Source: “Brown Fat Found in Thin Children Could be the New Antidote to Obesity: Study,”, 08/14/11
Source: “Newly-discovered human fat cell opens up new opportunities for future treatment of obesity,”, 05/02/13
Source: “Cold exposure prompts body to convert white fat to calorie-burning beige fat,”, 10/09/14
Photo via Visualhunt

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OVERWEIGHT: What Kids Say explores the obesity problem from the often-overlooked perspective of children struggling with being overweight.

About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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