Looking for a silver lining in the cold that’s gripping much of the country? The next time an icy blast of wind cuts through your flesh, remind yourself that it is also stimulating the growth and activity of brown fat, the so-called good fat that burns calories and produces heat.

Located in your chest and back, brown fat’s job is to protect your vital organs which, in winter, means giving you a way to generate additional heat for them. It’s more prevalent in newborns and hibernating animals, whose need for warmth is greater, but researchers discovered about five years ago that adults have some, too.

In contrast to white, or “bad,” fat, which stores energy as those bulges you’re trying to eliminate at the gym, brown fat is full of mitochondria, the glucose-burning power plants of cells, which give brown fat its color. People with more brown fat tend to be leaner and have lower blood sugar levels.

It takes a little time in the cold to crank up the brown fat, but temperatures don’t have to be down at the Polar Plunge level. When researchers exposed people to temperatures of 59 to 60 degrees for two to six hours over 10 consecutive days, they found immediate increases in brown fat activity. In another study, men who slept in rooms for a month at 66 degrees increased their brown fat and its activity by 30 percent to 40 percent. When the night-time temperature was raised to 80 degrees for another month, their brown fat stores declined below baseline levels.

This information has intrigued researchers who wonder whether stimulating brown fat might help in the battles against obesity and Type 2 diabetes.

How does this work? In a study released Thursday, University of California, Berkeley, researchers said they had identified the protein critical to the formation of brown fat. Exposure to increased levels of “transcription factor Zfp516” helped mice gain 30 percent less weight than other mice when both were fed the same high-fat diets. They also found that it helped “brown” that nasty white fat, though other researchers did not report this result.

In an interview, Hei Sook Sul, who led the research, said that in the laboratory, the same process worked on human cells, though the process has not been tested in humans themselves.

She said it’s impossible to determine how long an individual needs to be in the cold to kick-start the process, but recommended giving it a try at safe exposures.

“Get out,” said Sul, a professor in the university’s Department of Nutritional Science and Toxicology. ” The more you do it, the more energy you will lose.”

via A blast of cold jump-starts fat burning and generates body heat – The Washington Post.

An “imaginary meal” pill is the latest weapon developed by scientists to fight obesity.

The pill tricks the body into thinking it has consumed a large amount of calories – as if you have just eaten a substantial meal.

In early tests on mice it effectively halted weight gain, lowered cholesterol, controlled blood sugar, and reduced levels of unhealthy white fat.

US lead scientist Dr Ronald Evans, director of the Salk Institute’s Gene Expression Laboratory in La Jolla, California, said: “This pill is like an imaginary meal. It sends out the same signals that normally happen when you eat a lot of food, so the body starts clearing out space to store it. But there are no calories and no change in appetite.”

The drug, fexaramine, activates a protein called the farensoid X receptor (FXR) that plays a role in how the body releases bile acids from the liver, digests food and stores fats and sugars.

At the start of a meal, FXR prepares for an influx of food, not only triggering bile acid release but also altering blood sugar levels and instigating the burning of some fats.

Other drugs have been developed that act on FXR pathways, but they affect several organs and have unwanted side effects. An important feature of fexaramine is that it only functions in the gut and does not dissolve into the blood like appetite suppressants or caffeine-based diet drugs.

Since it does not reach the bloodstream it is likely to be safer than other FXR-targeting drugs, say the researchers who are working to set up clinical trials that will test fexaramine’s effectiveness in human patients.

Obese mice given a daily dose of the drug for five weeks stopped gaining weight, lost fat, and had lower blood sugar and cholesterol levels than untreated mice.

They also experienced a rise in body temperature, a sign that their metabolism was ramping up. Some of the deposits of white fat in their bodies were converted into the healthier form of calorie-burning “brown” fat.

The drug even affected bacteria in the guts of the mice, although what these changes mean is not yet clear.

Dr Evans compared fexaramine’s effect in the intestine to the start of a relay race.

“The body’s response to a meal is like a relay race, and if you tell all the runners to go at the same time, you’ll never pass the baton,” he said. “We’ve learned how to trigger the first runner so that the rest of the events happen in a natural order.”

via ‘Imaginary meal’ pill makes you feel full and burns fat – Telegraph.