Though body fat often gets a bad rap in our culture, we all need a certain amount of it to be healthy and stay alive. Fat helps to protect and cushion our vital internal organs, is a storage source for energy, helps regulate our hormones and our body temperature and plays an important role in immune function. Science continues to uncover interesting and unexpected ways that adipose tissue operates in our bodies.

Fats have various hues

Not only does fat play multiple roles in our body’s functioning, it also comes in at least three types: white, brown and beige. White fat is the most common type and what we are generally referring to when we talk about body fat. This type is also sometimes referred to as yellow fat. The primary role of white fat is as a storage place for extra energy. This source of energy is particularly important for endurance exercise, when the body accesses a significant amount of potential fuel from white fat reserves. 

Brown fat is also metabolically important, but functions very differently than white fat. This type of fat helps to regulate body temperature by creating heat that provides warmth in cold temperatures. Human infants and hibernating mammals have the highest levels of brown fat, but human adults also have some. Research is beginning to show that there may be ways we can increase levels of brown fat in order to promote healthier, more balanced metabolisms and potentially facilitate weight loss for people with that goal. 

Beige fat is another type of fat that is only beginning to be studied and understood. Like brown fat, beige fat is metabolically active and helps to burn calories instead of storing them. This type of fat is stimulated by the hormone irisin, which muscle cells create during exercise. Both brown fat and beige fat contain energy-burning mitochondria, which contain iron and are the cause of the darker colors.

How brown fats aid metabolism

There is some research that adults with higher levels of brown fat tend to be metabolically healthier. This may be because brown fat uses extra sugar and fat molecules to create heat to help regulate body temperature, helping to burn off excess calories and keep the body’s systems in balance. Most brown fat is found in the neck and spine and is activated by cold temperatures. 

In one study, people with higher levels of brown fat were less likely to have type 2 diabetes, cardiovascular disease, heart failure or high blood pressure. These benefits even extended to people who had higher levels of white fat, showing that brown fat has the power to protect people with varying body compositions. 

In another study of young men those with higher levels of brown fat were found to have lower levels of branched chain amino acids (BCAAs) in their bloodstreams. High levels of BCAA’s in the blood are associated with a high risk of metabolic disorder, future insulin resistance, type 2 diabetes, heart disease and obesity.

Can we boost brown fat levels?

Considerable research shows that being exposed to cold temperatures promotes the formation of additional brown fat. Because humans don’t like being cold for long periods of time, the majority of this research has been performed on mice or separate human tissue. One human study exposing young men to mildly cold temperatures (66° F) for 10 hours each evening increased brown fat levels by 42% and improved insulin sensitivity. This demonstrated that brown fat levels can be raised in adult humans and that tolerating extreme cold is not necessary to facilitate this process. These changes were reversed when the subjects began sleeping in a warmer environment, suggesting that ongoing cold therapy may be needed to stimulate brown fat levels.

For people who don’t want to tolerate cold temperature, medication may be able to stimulate increased brown fat levels. Women who took a drug called mirabegron for 4 weeks were able to increase their brown fat levels, insulin sensitivity and their resting metabolic rates by 6%. They also had higher levels of HDL or “good cholesterol.” This drug—which is already approved for the condition of overactive bladder—may not only be able to stimulate the production of brown fat but also encourage white fat cells to break down and release stored fat. Ongoing research and approvals are needed before mirabegron may be officially used for this purpose. 

All three types of fat play important roles in helping the body to thrive and stay metabolically healthy. Science continues to explore how each fat operates and how we can encourage healthy, balanced metabolisms.