What Exactly Is Brown Fat, and Does It Have Any Real Health Benefits?

When you hear “fat,” you might think about weight or certain health issues. But not all fat is bad or unhealthy — this goes for the fat you eat, as well as the fat found in your body. 

Your body needs some fat to protect your organs and keep you healthy. Scientists think that brown fat, specifically, might have some unique health properties.

Spoiler alert: More research is needed to understand brown fat and the role it might play in metabolic health. We’re also still figuring out how to increase brown fat, and whether that’s even a good idea. Here’s what we know so far. 

What is brown fat, and how is it different from white fat?

Brown adipose tissue, or brown fat, is a type of body fat that helps maintain our internal temperature. In doing so, it may play a role in our metabolism, some research suggests. This is different from white fat, or the main type of fat found in an adult’s body. White fat’s job is to store calories (energy).

Brown fat also differs from white fat because of its distinctive color. Compared to white fat, brown fat contains more mitochondria (parts of a cell that store energy). The iron in these mitochondria is what gives brown fat its color.

Where is brown fat located?

Brown fat is found in your neck, and around the kidneys, adrenal glands, and the aorta. When you’re born, most of the fat in your body is brown fat. Babies need brown fat because they can’t regulate their body temperature as well as adults. As you get older, you lose your brown fat because you’re able to regulate your body temperature in other ways. 

What causes brown fat?

Some adults may have more brown fat than others. Brown fat can be hard to measure, and things like age and sex likely affect how much of it we have in our bodies. Surrounding temperature and diet might also affect the amount of brown fat we have in our bodies. But even adults with higher levels of brown fat don’t have a lot of it. And the brown fat adults store also becomes less active. When brown fat isn’t active, it doesn’t burn any energy.  

Is brown fat better for you than other types of fat?

It’s not fully clear yet. Animal studies suggest brown fat might play a role in metabolism. When it’s active, brown fat uses energy from glucose (sugar), protein, and fat to regulate body temperature. It may also preferentially use certain forms of energy, which can affect the body’s metabolic health. As a result of this function, scientists want to know whether having more active brown fat could play a role in addressing obesity and diabetes. 

However, the data suggesting that brown fat has potential benefits in humans is lacking overall. Let’s take a closer look.

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Can brown fat help with weight loss?

No conclusive evidence shows that having more active brown fat leads to weight loss. The claim comes from a few small studies that examined whether cold temperatures can activate brown fat.

Exposure to cool air (61°F to 66°F or 16°C to 18°C) or cold water (around 46°F or 8°C) may prompt brown fat to generate heat. Brown fat generates heat by converting stored calories into thermal energy — so it literally burns calories. This process warms the body from the inside out to maintain body temperature. 

But brown fat’s calorie-burning potential might not amount to much. The body uses other more efficient ways to warm up in cold weather. A small study suggests that brown fat may only burn around 20 calories in cold temperatures.  

Can brown fat help improve blood sugar levels?

It’s not clear that brown fat helps improve blood sugar levels. A small study suggests that activating brown fat might be associated with lower blood sugar levels in people with Type 2 diabetes. But scientists think this has more to do with exposure to the cold rather than brown fat activity.

In another small study, scientists observed that brown fat was better at regulating blood sugar levels than white fat. In particular, brown fat used more blood sugar than white fat when participants were injected with insulin. Insulin is a hormone that helps your body convert blood sugar into energy. But since adults don’t have much brown fat, it’s not clear if this has any effect on blood sugar management in real life. 

Can you increase brown fat?

There are no proven methods of raising brown fat levels in the body. Scientists have also looked at ways to make brown fat more active. But right now, it’s unclear if either of these things will ever be possible or beneficial. Today, there are only two known potential lifestyle habits that might increase brown fat levels or activity.

Cold exposure

A review of studies suggests that colder temperatures (around 61°F to 66°F or 16°C to 18°C) are linked to more brown fat activity. Other studies suggest that submerging your hand or foot in cold water or wearing cold vests might increase brown fat activity. But it’s not worth your time or effort to try this. These studies looked at whether cold exposure activates brown fat — a concept that isn’t exactly new in science. None of these studies looked at whether, once active, the brown fat burned enough calories to impact people’s metabolic health. 

There are some claims that similar approaches — like cold plunges or ice baths — can promote weight loss. But these claims aren’t supported by science. They have been studied for sore muscles rather than weight loss. And doing a cold plunge or ice bath may not be safe for everyone, since exposure to very cold temperatures can lead to cold injuries like frostbite and increased heart rate and blood pressure.

Foods and supplements

In humans, capsinoids — compounds found in red and chili peppers — have been linked to higher brown fat activity. But based on available information, you may need at least a 9 mg capsinoid supplement to see any increase in brown fat activity. Whether such high doses of capsinoids are safe requires more long-term research. And like the cold studies, this study didn’t look at whether participants ended up with improvements in their metabolic health.

Other foods and supplements are also reported to increase brown fat activity. These include:

• Green tea

• Turmeric

• Omega-3s

• Resveratrol

But these are based on animal studies only. Animals have a very different metabolism than humans, so we can’t make any conclusions based on these studies.

Are there any risks of making brown fat more active?

Yes. As much as there is an interest in understanding whether brown fat can help improve metabolic health, experts have raised concerns about brown fat activity and potential heart problems.

In a small study, scientists looked at the effects of cold temperatures on men with and without high blood pressure. All participants were exposed to a temperature of 14°F (-10°C) for 15 minutes. Researchers noticed a significant increase in blood pressure and heart strain in both groups. Another review of studies found similar associations, but also found that blood pressure increases were more significant in people with existing heart conditions. 

These results present additional challenges in trying to make brown fat more active. Scientists need to find a way to make brown fat active and to do it safely. Otherwise, the risks of activating brown fat will outweigh potential health benefits.  

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Written by:

Victoria Eaton, RDN, LDN, IFNCP

Victoria Eaton, RDN, LDN, IFNCP began her career in the functional medicine space in 2015. She has experience in private practice and working with individuals with digestive issues, chronic migraines, and macular degeneration.

Edited by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. A pulmonologist and hospitalist, she practiced and taught clinical medicine at hospitals in London for a decade before entering a career in health education and technology.

Reviewed by:

Sarah Gupta, MD

Sarah Gupta, MD, is a licensed physician with a special interest in mental health, sex and gender, eating disorders, and the human microbiome. She is currently board certified by the American Board of Psychiatry and Neurology.

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