Brown Fat? Give Me Some More of That!

For most people, the word "fat" brings up undesirable associations: stubborn muffin tops, restrictive diets, heart disease. When exercising and dieting, we generally try to decrease body fat levels because they are harmful in excess.

But what about brown fat? It sounds even more disgusting than your typical "white fat", but brown fat is actually more complicated – and beneficial!

Brown fat cells are composed of many small, oily droplets, and contain the brown, kidney-shaped organelles known as mitochondria. In brown fat cells, mitochondria burn up the droplets around them to produce heat. In contrast, white fat cells lack mitochondria, and are formed of larger single oily drops.

What does that mean? Through generating heat, brown fat burns calories, and white fat does not.

Who has brown fat?

Brown fat is primarily found in babies. Because infants cannot shiver, the brown fat helps generate excess heat that helps keep them warm. While much of it disappears with age, it turns out that adults have some small stores of brown fat, mostly between the shoulder blades.

You're probably wondering if you have brown fat. Sadly, BodySpec's DXA scan cannot test clients for brown fat. The only way to measure it is through a PET (positron emission tomography scan) which involves injecting you with radiolabeled glucose. However, we do know the following:

• Younger people have more brown fat than older people
• Leaner people have more brown fat than obese people do
• People with normal blood sugar levels have more brown fat than those with high blood sugar

But regardless of how much actual brown fat you have, there's some good news. You can actually get your white fat to act like brown fat! This calorie-burning white fat is called "beige fat".

How do I turn my white fat into beige fat?

Several research studies have found ways to trigger white fat to start turning beige and burning calories.

• Turn down the thermostat! Cold temperatures may activate your brown fat and help you lose white fat. Shivering muscle triggers a hormone called irisin, which "fires up" white fat cells to begin burning heat.
• Exercise! Moderate physical activity that works your muscles also triggers irisin.
• Get enough sleep! When you're sleeping, you produce melatonin, a hormone with many beneficiary roles, including stimulating the appearance of beige fat.

So the next time you do these things, remember that as you're changing your lifestyle, you're also changing your fat cells – for the better!