Weight Loss Treatment Could One Day Turn 'Bad' White Fat Into 'Good' Brown Fat, Study Shows

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Scientists have converted white fat to brown fat in a bioreactor. Getty Images

So-called "bad" fat has been turned into "good" fat which burns more energy, by scientists who hope the technique could one day be used to tackle the obesity crisis.

The research hones in on two types of fat in the body. Less healthy white fat gathers around the belly and is used as an energy store. Meanwhile, brown fat is stored around the neck, torso and in white fat reserves, and is used to keep us warm.

Decades-worth of research on rodents suggests that when the body uses up brown fat, it burns a relatively large amount of energy considering its size. Scientists believe if we have more brown fat in our bodies, it should be easier to lose weight. And as more than one third of adults in the U.S. are obese, understanding how the body processes white and brown fat could be an important tool for tackling the epidemic.

To pinpoint whether the differences in these fats could be harnessed to help people lose weight, the team at NYU Winthrop Hospital converted the fat cells of humans in a bioreactor. In the future, scientists hope to remove white fat from the body, dose it with chemicals for several weeks in a bioreactor to convert it to brown fat, and inject it back in the body.

"The method utilizes fat grafting procedures commonly performed by plastic surgeons, in which fat is harvested from under the skin and then retransplanted in the same patient for cosmetic or reconstructive purposes," Brian Gillette, director of engineering at NYU Winthrop Hospital and author of the study published in Scientific Reports told Newsweek.

Gillette explained to The Guardian that brown fat is "one of the most metabolic tissues in the body." He estimates between 50 to 100g of brown fat, which is around the amount found in an adult, can account for 20 percent of the energy a person uses in a day.

In mice that had been fed a high-fat diet, scientists converted the white fat into brown fat and replaced it in their bodies, finding it remained brown for eight weeks. However, the mice did not lose more weight than the control group and further research is needed to understand how it could be used as an approach for weight loss.

If replicated in human trials, such a technique could help patients avoid the side-effects of weight loss drugs, and bariatric surgery, which carries the risks of major surgery.

"This innovative approach to increasing brown fat is potentially safer than drugs because the only thing going into the patient is their own tissue, and it's highly controllable since the amount of brown fat injected can be tuned," Gillette told Newsweek. "The process is also so simple that it could potentially be performed using an automated system within a doctor's office or clinic."

Previous studies have shown that brown fat burns energy when the body is exposed to the cold, but training it to do so can involve weeks of exposure to chilly temperatures for several hours.

Michael Symonds, deputy head of Nottingham University's School of Medicine, Faculty of Medicine and Health Sciences, who has researched fats and was not involved in the study, told Newsweek that the study was "somewhat incomplete."

"[The researchers] need to see whether the same outcomes are seen in other strains of mice and when housed at thermoneutrality rather than standard temperature of 20 degrees Celsius [68 degrees Fahrenheit) which is cool for a mouse," he said.

This piece has been updated with comment from Michael Symonds and Brian Gillette