What color is your fat?
Losing weight isn’t easy as evidenced by the obesity epidemic in this country. Appetite suppressants, fad diets, supplements or gastric band surgery are regularly reported in the news media to achieve results. However, if that were the answer, there wouldn’t be a new fad seemingly appearing every other month as an answer to this problem.
Scientists state that adipose tissue (fat) comes in at least three colors, white, beige and brown. White adipose tissue (WAT) is lazy and stores energy. Brown adipose tissue (BAT) is involved in thermoregulation which creates heat and uses energy. Beige or (Brite) is a hybrid of both. What gives BAT its brown color is the mitochondria. It’s the mitochondria in the cells of the BAT that enables it to burn fuel for energy; by some estimates up to five times more calories than WAT. BAT also has more capillaries than WAT because of its higher oxygen consumption. Babies, as well as animals that hibernate have a larger percentage of BAT. For babies, about 5% of their body weight is made up of BAT, and adults are less than that. Evidently even in small amounts, BAT serves as a protective mechanism against hypothermia, which is why babies don’t shiver even after taking them out of a bath or why we sometimes hear miraculous stories of a baby surviving severe cold exposure. It was assumed that all brown fat disappears during childhood, but new findings revealed otherwise.
The caloric vs. the endocrine debate
WAT is generally believed to be the result of overeating and excess calorie storage. Humans typically store this fat in areas above the waist. BAT is typically stored in the front and back of the neck and in the upper back. WAT is associated with the commonly seen chronic degenerative problems in our society such as type 2 diabetes, high blood pressure, Alzheimers disease, and more. Others think that WAT is the result of endocrine disorders such as thyroid issues and insulin dysregulation. It is the insulin piece that is most easily addressed because both the caloric and endocrine debate have a common thread in the insulin connection to the accumulation of WAT.
The liver is high in acetyl CoA which results from the breakdown of both fats and carbohydrates and this is what dictates fuel use. According to Benjamin Bikman PhD, a professor of pathophysiology and biomedical scientist at Brigham Young University, “if insulin is high it will turn acetyl CoA into lipids (fats), and if insulin is low, acetyl CoA will turn into ketones. If insulin is high, BAT will convert to WAT. Conversely, ketones can convert WAT to BAT with low insulin”. Therefore, we can see why the ketogenic diet is so effective. By keeping carbohydrates to a minimum, you can avoid high insulin levels and you can preserve or develop more BAT that will turn your body into a ketone sourced metabolic burning machine. Some people feel taking exogenous ketones will help with this process too.
Another way that is gaining popularity to convert WAT to BAT is cold therapy such as cryotherapy. In a 2012 study, six men remained inactive for three hours while wearing a cold suit that circulated water with a temperature of 64.4 degrees Fahrenheit over their skin-cold enough to lower their body temperature without causing shivering. This way the researchers could be sure that most of the extra calories burned during those three hours were expended by brown fat cells rather than quivering muscles. The results were that the volunteers burned an extra 250 calories compared to what they would have used during three hours of inactivity at more typical indoor temperatures. A similar study was done using 12 young men in Japan last year and in both cases PET-CT scans indicated that either brown fat or beige fat activity had increased.
Adinopectin is a hormone that is released during cold exposure that breaks down fat and shuttles glucose into muscles (which can lower blood sugar). Low adiponectin levels are associated with obesity, diabetes and cardiovascular disease. It is also believed that cold therapy along with exercise increases the activity of a gene named UCP1 which seems to guide the conversion of white fat into beige fat. Dr. Bruce Spiegelman, professor of cell biology and medicine at Harvard’s Dana-Farber Cancer Center in Boston discovered a protein in 2007 called PRDM16 that appears to regulate the production of brown fat. Mice genetically altered to have more PRDM16 had greater BAT and calorie burn rate.
If the idea of getting cold isn’t your thing, then consider exercise. Two studies in 2012 showed that a hormone called irisin, which is released from muscle cells after exercise, coaxes white fat to behave like brown fat. In one of these studies, researchers injected mice with a gene that tripled the levels of the hormone in the blood of mice that were obese and had dangerously high amounts of sugar in their bloodstream. The mice lost weight and regained control of their glucose levels in just 10 days!
Researchers have been hard at work at trying to figure out a way of activating more beige and brown fat activity to address the most commonly seen chronic degenerative diseases occurring today. From this research some people are popularizing taking daily cold showers or going into a cryotherapy chamber where your body would be exposed to temperatures below -100 degrees centigrade for a couple of minutes. The same is true with taking exogenous ketones. However, simply turning down the thermostat in your house this winter, or regular exercise will work too. For some people, following the rules of the Ketogenic diet and intermittent fasting can be an effective way of achieving results. Clearly understanding the dynamic difference between white, beige and brown adipose tissue will give you the knowledge to understand on a deeper level what is really happening and some personal strategies to act upon.