What is brown fat?
You may be surprised to learn that the fat in your body is made up of different colors. Scientists have identified both white and brown fat. The brown color is also sometimes referred to as beige, brite, or inducible BAT.
What’s the purpose of body fat?
Each kind of fat serves a different purpose.
White fat, or white adipose tissue (WAT), is the standard fat you’ve likely known about your whole life. It stores your energy in large fat droplets that accumulate around the body. The accumulation of fat helps keep you warm by literally providing insulation for your organs.
In humans, too much white fat isn’t a good thing. It leads to obesity. Too much white fat around the midsection may also create a higher risk of heart disease, diabetes, and other diseases.
Brown fat, or brown adipose tissue (BAT), stores energy in a smaller space than white fat. It’s packed with iron-rich mitochondria, which is how it gets its color. When brown fat burns, it creates heat without shivering. This process is called thermogenesis. During this process, the brown fat also burns calories. Brown fat is highly regarded as a possible treatment for obesity and some metabolic syndromes.
Scientists used to believe that only babies had brown fat, which makes up about 5 percent of their total body mass. They also thought this fat disappeared by the time most people reached adulthood.
What researchers now know is that even adults have small reserves of brown fat. It’s typically stored in small deposits around the shoulders and neck.
How to get brown fat
In a way, brown fat is “good” fat. Humans with higher levels of brown fat may have lower bodyweights, for example.
All people have some “constitutive” brown fat, which is the kind you’re born with. There’s also another form that’s “recruitable.” This means it can change to brown fat under the right circumstances. This recruitable type is found in muscles and white fat throughout your body.
There are certain drugs that can cause the browning of white fat. Thiazolidinediones (TZDs), a drug used to help manage insulin resistance, can help with brown fat accumulation.
However, this drug is also associated with weight gain, fluid retention, and other side effects. So, it can’t be used as a quick fix for people looking to gain more brown fat.
Turn the temperature down
Exposing your body to cool and even cold temperatures may help recruit more brown fat cells. Some research has suggested that just two hours of exposure each day to temperatures around 66˚F (19˚C) may be enough to turn recruitable fat to brown.
You may consider taking a cold shower or ice bath. Turning the thermostat down a few degrees in your home or going outside in cold weather are other ways to cool your body and possibly create more brown fat.
In one study, researchers overfed mice and found that those with more brown fat burn more calories. They stayed leaner and healthier this way. They were also protected from obesity and other metabolic diseases.
But that doesn’t mean you should start eating more to activate brown fat cells. Overeating is still considered a major cause of obesity. More research is needed before this method can be recommended. For now, continue to follow a well-balanced diet made up of whole foods.
Other research on mice suggests that a protein called irisin may help transform white fat to brown. Humans also produce this protein. Researchers uncovered that people who are sedentary produce far less irisin compared to those who exercise often. Specifically, levels are increased when people do more intense aerobic interval training.
Exercise is highly recommended by doctors to fight obesity and keep the cardiovascular system running strong. Current physical activity guidelines for adults include doing one of the following every week:
- 150 minutes of moderate activity, such as walking or playing tennis
- 75 minutes of vigorous activity, such as jogging or swimming laps
There’s not enough research to know for sure if exercise creates more brown fat. But exercise has so many health benefits that you should do it regardless.
Brown fat and research
Researchers are still trying to understand the genes that control how white and brown fat develops. In one study, scientists engineered mice to be born with very little brown fat by limiting a protein called Type 1A BMP-receptor. When exposed to cold, the mice created brown fat from their white fat and muscles anyway, showing the power of recruitment.
Researchers have also discovered that a certain protein called early B-cell factor-2 (Ebf2) may play a key role in building brown fat. When engineered mice had exposure to high levels of Ebf2, it transformed white fat to brown fat. These cells consumed more oxygen, which is a sign that the brown fat was indeed producing heat and burning calories.
Can brown fat help treat or prevent conditions like diabetes?
A review on various studies has shown that brown fat burns calories and may help control blood sugar and improve insulin levels, decreasing the risk for type 2 diabetes. It may also help with removing fats from the blood, decreasing the risk for hyperlipidemia. Other studies show promise for brown fat’s role in treating obesity.
It’s important to note that until recently, most studies on brown fat have been done on animals, particularly mice. More research is needed on humans.
More research is needed before doctors can hand out a pill or other quick fix to convert white fat to brown. Before you start taking ice baths, eating everything in sight, or turning down your thermostat, consider basic diet and exercise.
These healthy lifestyle habits have the power to help you shed extra pounds, keep your heart and lungs strong, and ward off heart disease, diabetes, and other obesity-related diseases.