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Tuesday, July 22, 2014

TYPES OF BODY FAT

For quite some time science has recognized the existence of two distinct types of body fat.

 
White fat, the kind that makes your buns jiggle, is tough to get rid of. Too much of it increases the risk of heart disease and diabetes. Each white fat cell stores energy in the form of a single large, oily droplet but is otherwise basically inert. Because the metabolic rate of white fat is slow, the more of it you have, the fewer calories you burn.

Brown fat, in contrast, contains many smaller droplets, as well as chestnut-hued metabolic machines called mitochondria, the cellular powerhouse that burns up brown fat to generate heat. Until recently it was believed that brown fat was found exclusively in babies. Babies, who have not developed the ability to shiver to maintain body temperature, rely on thermogenic deposits of brown fat to stay warm. These deposits typically accumulate in the neck and around the shoulders.
 
 
Investigators assumed that all brown fat disappears by adulthood, but new findings reveal that adults have brown fat too, and that increasing it, or converting white fat into brown fat, can alter metabolism in a way that leads to weight reduction.

Of course this has spurned scientists to search for the magic pill that activates brown fat, but till now the efforts have proven futile. Thus far the easiest way to get brown fat revved up and burning in the adult body has been by exposing people to low temperatures.
 
In a 2012 study, experimenters clad volunteers in a cold suit that circulated water with a temperature of 64.4 degrees and then made them sit down and wear the suit for three hours. The temperature was cold enough to stimulate brown fat without being so cold as to induce shivering, which on its own burns calories. Sure enough, subjects burned an extra 250 calories compared with those who were inactive at more typical indoor climates. 250 calories does not seem like much, but over a month that translates to a couple lbs, or over 20 lbs per year of pure fat burned. In addition, researchers learned that brown fat's benefits extend beyond fat-burning. Brown fat preferentially burns triglycerides in the blood, reducing levels that otherwise might lead to heart disease, stroke and diabetes.
 
Scientists believe that low temperatures increase the activity of a gene named UCP1, which helps convert white fat into beige fat. Beige is a mixture of brown and white. Part of the reason for the obesity epidemic, in addition to unhealthy diet and sedentary lifestyle, could be lack of exposure to temperature variation. Most of us spend most of the day indoors in a layer or two of clothing and with the thermometer set to a comfortable 75 degrees. Comfortable, but not cool enough to induce a calorie burn.
 
If blasting the air conditioning or wearing a cold suit just to burn a few hundred calories doesn't sound like fun, take heed. We've got one more trick up our sleeve. The old-fashioned calorie burn.

Like slow temps, exercise has also been shown to increase UCP1 activity in brown fat, making it more active which results in more calories burned during activity and at rest. What's more: As you age, the quantity and efficiency of mitochondria decrease, due to the body's waning ability to make an enzyme called AMP-activated protein kinase (AMPK), which functions to increase mitochondria in muscles. Since mitochondria are responsible for burning fat and sugar for energy, anything that inhibits them interferes with this ability and lowers your metabolic rate, leading to weight gains and weight-related health problems.
 
It turns out that exercise increases AMPK, which means that exercise's ability to keep you lean is two-fold. Not only does it activate brown fat, but it also turns on the mitochondria body wide - preventing you from...getting wide. Add to this the innate calorie-burning that comes from moving around, and you have a happy triad. Feel the burn today!


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