Meilian Liu, PhD Meilian Liu, PhD

Don't Fear the Fat

Studying the Good, the Bad and the Beige

Trying to squeeze yourself into last year’s jeans? You’re not alone. At a time when nearly 40 percent of adults are obese, and obesity-related conditions like heart disease, diabetes and high blood pressure are on the rise, it’s no wonder that Americans are preoccupied with fat – and how to get rid of it.

But back in 2009, researchers made a surprising discovery: there are two types of fat in the body, and one of them is actually good for you. So what is good fat, where does it come from and how do we get more of it?

This “good” fat – typically brown in color, as opposed to white “bad” fat – is primarily located around the neck and shoulders and is only activated when the body is very cold, because it generates heat. In fact, brown fat helps to protect babies because they are unable to shiver.

There’s more good news. Everyone has some amount of brown fat, but those with a lower body mass index – or BMI – tend to have more of it, which leads scientists to believe that brown fat can make our bodies more energy efficient and lead to better overall health.

There is also an intermediate type of fat, referred to as beige fat – and it likely could be the key to reducing obesity. Meilian Liu, PhD, an assistant professor in the Department of Biochemistry & Molecular Biology at the UNM Health Sciences Center, is trying to use chemical signals to turn the bad fat – also known as white adipose tissue – into beige fat through a process called, appropriately enough, “browning.”

Liu’s interest was piqued when she observed that brown fat stem cells resembled muscle stem cells, in that they had a lot of mitochondria – the fat-burning power plants inside our cells that release energy.

If these brown fat-burning fat cells are found in adults, Liu wondered, can you make more of them? Her studies have revealed that white fat could turn beige, and subsequently burn more fat when specific chemical signals were applied.

Now, Liu is trying to determine whether a skin patch releasing a special hormone called prostaglandin can speed up the browning of white fat in targeted areas, like the midsection. Those results will be forthcoming.

Liu has been incredibly prolific during her time at UNM, publishing 13 research articles and authoring four invited reviews. She is studying the complex biology of adipokine-mediated signaling. Adipokines are signals released from these different types of fat. She has also been investigating the body’s immune response to white fat, more specifically, how to decrease it to lessen obesity-related consequences.

What is the best way to fight the battle of the belly bulge?

While diet and exercise remain the best ways to be healthy and stave off obesity and its many consequences, Liu herself has been practicing “intermittent fasting.” This dietary technique facilitates the browning of white fat through a variety of complex processes that stimulate autophagy, the cell’s basic garbage disposal process. Since starting intermittent fasting, Liu reports feeling more “energetic and youthful.”

UNM provides a very supportive atmosphere for researchers, Liu says, because it is “small, more intimate and offers great mentorship.”

“It also provides access to small pilot grant programs, with excellent opportunities for intramural funding and great research cores, like the new Autophagy Inflammation and Metabolism Center,” Liu adds. These grants have led to the generation of the pilot data she used to obtain a major research grant that is currently funding her laboratory.

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