Brown Fat

Overview

What is brown fat?

Brown fat, also called brown adipose tissue, is a type of body fat that keeps you warm when you get cold. Brown fat also stores energy and helps your body burn calories. Brown fat starts working (activates) in cold temperatures.

What are the types of fat in my body?

There are different types of fat in your body. Healthcare providers identify each type of fat by its color and function, including:

  • White fat: Most of the fat in your body is white fat. White fat stores energy in various places around your body. White fat insulates your organs. Too much white fat leads to obesity.
  • Brown fat: Brown fat is smaller than white fat. It stores energy and burns that energy to regulate your body temperature. Brown fat helps you burn calories by creating heat right before your body starts to shiver (thermogenesis). It also helps regulate sugar (glucose) and fat metabolism.
  • Beige fat: Beige fat is a combination of white and brown fat cells. These cells burn calories to regulate body temperature by converting white fat cells to brown.

Function

What does brown fat do?

Brown fat is responsible for producing heat to warm the blood in your body. You’ll notice brown fat burning right before you start to shiver because the fat activates (turns on) in cold temperatures. It produces heat by breaking down blood sugar (glucose) and molecules of fat. This process (thermogenesis) creates heat to help you maintain your body temperature.

How does brown fat help my body?

Brown fat helps your body in different ways including:

  • Maintains your body temperature.
  • Produces and stores energy.
  • Burns calories.
  • Helps control blood sugar and insulin levels.

Anatomy

What does brown fat look like?

Tiny molecules make up brown fat and those molecules are fat cells. Molecules consist of fatty acids and glycerol. The anatomy of brown fat resembles muscle more than it resembles other fat in your body because the cells that store brown fat in tissues (adipocyte) are smaller.

When fat collects within your body, fat molecules lump together to create a mass. Brown fat looks like a small, brown, lumpy oval.

Why is brown fat the color brown?

Fat in your body has different colors that designate its function. Brown fat is brown because the fat cells are full of mitochondria. Mitochondria is made up of a lot of iron, which gives brown fat its color.

Where is brown fat located?

Brown fat in newborns is located in their back, neck and shoulders. During childhood and adolescence, brown fat scatters around the body. Brown fat in adults is located around the neck, kidneys, adrenal glands, heart (aorta) and chest (mediastinum).

How much brown fat is in my body?

The amount of fat in your body varies from person to person. You have less brown fat than white fat in your body.

In newborns, brown fat makes up 2% to 5% of their total body weight. During childhood and adolescence, the amount of brown fat reduces. As an adult, you have a small amount of brown fat. People who are lean, like athletes, have more brown fat in their bodies than others.

Conditions and Disorders

What are common conditions that affect brown fat?

Several conditions affect brown fat in your body, including:

  • Anorexia nervosa: This eating disorder causes a person to lose both white and brown fat. The condition affects how your body produces energy, and you could have trouble regulating your body temperature.
  • Congenital leptin deficiency: Leptin is a hormone that fat cells in adipose tissue release to control body weight. If you have a leptin deficiency, your body’s fat cells aren’t producing enough of the leptin hormone and you’re at risk of obesity.
  • Lipodystrophy: This condition affects the amount and distribution of fat tissue (adipose tissue) in your body. Lipodystrophy makes it difficult for your body to store the energy you receive from food.
  • Lipoma: Lipomas are lumps of fatty tissue underneath your skin. This condition doesn’t cause pain or health problems, but healthcare providers can remove the fatty tissue if it bothers you.

What are common tests to check the health of my brown fat?

Your provider will offer tests to check the health of the fat cells in your body through a couple of tests, including:

Care

How do I get fat in my body?

You get fat from the foods you eat. Fat is essential because it produces energy. There are a lot of different foods that provide good sources of fat, including:

  • Avocados.
  • Nuts and seeds (cashews, chia seeds, flax seeds).
  • Fish (salmon, fresh tuna).
  • Yogurt.

Always combine foods that have good fat with vegetables, whole grains, protein and dairy to eat a well-balanced diet.

Foods you should avoid to prevent unhealthy fat from collecting in your body include:

  • Saturated fats (processed foods, margarine, white chocolate, desserts).
  • Trans fats (fried foods, frozen foods).

How do I increase the amount of brown fat cells in my body?

People might want to increase the amount of brown fat in their bodies if they want to lose weight and burn calories. You can take steps to increase the amount of brown fat in your body by:

  • Lowering the temperature: Brown fat activates at colder temperatures, right before you start shivering. Some studies suggest turning down the thermostat, taking a cold shower or an ice bath could activate brown fat to help your body produce more to burn more calories.
  • Adding iron to your diet: You build fat from the foods you eat. As brown fat is rich in iron, choose iron supplements or food items rich in iron, like meat and seafood, whole grains, leafy vegetables and beans, to make sure your body gets enough iron to keep your fat cells healthy.
  • Eating a well-balanced diet: Nutrition is vital for your health, especially if you want to increase brown fat in your body. Research shows that some foods like apples and dried fruit contain a chemical that activates brown fat production called ursolic acid. Eat enough food to satisfy your appetite and avoid overeating or eating processed foods.
  • Exercising: Staying active is a great way to maintain good health. Studies suggest that exercise activates your body’s blood hormone irisin, which tells white fat in your body to burn like brown fat. This process creates “beige fat.”

A note from Cleveland Clinic

Brown fat positively influences the way your body works by maintaining your body temperature in cold conditions and producing energy. Take steps to keep the brown fat in your body healthy by eating a well-balanced diet, exercising and lowering the temperature in controlled environments by taking a cold shower or an ice bath a couple of times a week. If you’re unsure what foods or activities are right for your body, talk with a healthcare provider.

Last reviewed by a Cleveland Clinic medical professional on 08/07/2022.

References

  • Gaspar RC, Pauli JR, Shulman GI, et al. An Update on Brown Adipose Tissue Biology: A Discussion of Recent Findings. (https://doi.org/10.1152/ajpendo.00310.2020) American Journal of Physiology. Endocrinology and Metabolism, 320(3), E488–E495. Accessed 8/7/2022.
  • Merck Manual. Carbohydrates, Proteins and Fats. (https://www.merckmanuals.com/home/disorders-of-nutrition/overview-of-nutrition/carbohydrates,-proteins,-and-fats?query=brown%20fat) Accessed 8/7/2022.
  • Mescher AL, ed. Adipose Tissue. (https://accessmedicine-mhmedical-com.ccmain.ohionet.org/content.aspx?bookid=2430&sectionid=190277324) In: Junqueira’s Basic Histology: Text and Atlas, 15e. New York, NY: McGraw Hill; 2018. Accessed 8/7/2022.
  • Society for Endocrinology. Several pages reviewed. (https://www.yourhormones.info/endocrine-conditions/lipodystrophy/) Accessed 8/7/2022.
  • U.S. Department of Health & Human Services. Several (https://directorsblog.nih.gov/2013/03/26/brown-fat-white-fat-good-fat-bad-fat/) pages reviewed. (https://directorsblog.nih.gov/2013/03/26/brown-fat-white-fat-good-fat-bad-fat/) Accessed 8/7/2022.
  • Van Marken Lichtenbelt WD. Human Brown Adipose Tissue-A Decade Later. (https://doi.org/10.1002/oby.23166) Obesity (Silver Spring, Md.). 29(7), 1099–1101. Accessed 8/7/2022.
  • Xiao Y, Liu D, Cline MA & Gilbert ER. Chronic Stress and Adipose Tissue in the Anorexic State: Endocrine and Epigenetic Mechanisms. (https://doi.org/10.1080/21623945.2020.1803643) Adipocyte. 2020: 9(1), 472–483. Accessed 8/7/2022.

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