Body Fat Percentage: Good vs. Bad Body Fat
April 29, 2021
Brown. White. Beige. The only time color matters is when it comes to the types, and amounts, of fat we have in our bodies.
When we think about losing weight, most of us envision slimming down by building muscle and reducing body fat levels. But what many people don't know is that we actually have several different types of body fat, or adipose tissue. Each type of fat has a unique makeup and behavior within the body. Distinguishing between the function and characteristics of white, brown, and beige fat will inform your understanding of your body composition, which, in turn, informs healthy steps to boost wellness and reduce disease risk.
The deep dive: Different types of fat
Adipose tissue consists of fat storage cells nestled in the connective tissue throughout the body. These cells, called adipocytes, serve the critical function of energy storage and release. Simply put, without fat, we couldn't dance, work out, or complete any of the other activities on our busy schedules. Research has started to uncover enlightening information about the role of the three main types of adipose tissue, commonly called brown, white, and beige fat. Yes, that’s right, beige. On top of the better known brown and white adipose tissue, there is in fact a third type of fat, beige.
Makeup and development
Most white fat cells consist of just one large round drop of a fat substance known as a lipid, which the body converts to energy in the form of fatty acids. By contrast, brown fat cells are composed of many smaller lipid drops combined with iron-rich mitochondria, which provides the darker hue.
Scientists have found that exposure to low temperatures darkens white fat cells to a light brown color. The resulting substance is called beige, brown in white, or brite fat. Research indicates that this process, called browning, might happen not just when we shiver but also when we treat our bodies well with regular physical activity and good nutrition.
Fun fact: Despite the rainbow of color names we have for adipose tissue, most fat cells actually look yellow upon examination. According to the Cleveland Clinic, the yellow hue comes from the carotene in vegetables and grains we eat, which takes a long time to process.
Location and function
White fat develops in the connective tissues in the abdomen and under the skin. An excess of white fat cells causes us to become overweight or obese. When these cells occur deep within the body, they wrap around the internal organs as visceral fat, which dramatically increases the risk for countless chronic diseases and dangerous health events, including type 2 diabetes, breast cancer, cardiac arrest, stroke, and heart disease.
Brown fat spreads from the neck and collarbones down the shoulder blades and spine. These cells also collect around internal organs, where they create body heat from food energy. While scientists once thought brown fat only existed in newborns who cannot independently regulate their body temperatures, today, we know that individuals of all ages have varying amounts of brown fat.
Beige fat functions like brown fat but releases lower levels of UCP1, a protein that mitochondria need to burn calories. Like white fat, you'll find beige fat under the skin in the abdominal cavity and within the connective tissues throughout the body.
Action in the body
The body converts the food we eat into energy in the form of glucose. When we eat calories we do not burn off with physical activity, our white fat cells modify the glucose cells to lipids known as triglycerides, a type of cholesterol. White fat collects in the thighs, stomach, and hips so we can draw from these stores for energy in case of starvation. However, with too much glucose in the form of calories, these cells will keep growing.
The mitochondria in brown and beige fat draw in glucose and triglycerides for energy conversion. These cells also condense the energy into a smaller space than with larger white fat cells. That may explain why slimmer individuals tend to have more brown fat than those who are overweight and obese—and why it's so important to understand your body composition on the path to better health and wellness. Men's Journal reports that an adult in a healthy weight range has about 2 to 3 oz of brown fat.
Understanding the action of these different types of fat brings us to the bottom line. Excess white fat causes obesity and a host of related health complications, while brown and beige fat burn calories and reduce disease risk.
The showdown: Good vs. bad body fat
While we've established that we need body fat to survive and thrive, too much white fat, especially visceral fat, can lead to impacted wellness and chronic disease. Conversely, building beige and brown fat stores can help your body burn energy more efficiently, increasing your metabolism and helping you maintain a healthy body composition. Now that you know more than you ever thought you would about body fat, it's time to put your knowledge to the test by implementing these strategies to reduce white adipose tissue and build up brown and beige fat cells.
Fun fact: When we burn fat, we actually exhale it! Research shows that 80 percent of lost fat leaves the lungs as carbon dioxide.
Face down visceral fat
As described above, visceral fat consists of white fat cells that cluster around the internal organs deep within the abdominal walls. By contrast, subcutaneous fat exists just under the skin and becomes visible when the cells expand with excess glucose.
The organs become damaged by hormones and chemicals released by visceral fat, lowering metabolism and leaving the body susceptible to disease. For example, a study published in the journal Diabetes Care found that visceral fat releases cytokines that create inflammation and insulin resistance, leading to heart disease, cancer, type 2 diabetes, and obesity.
Despite its dangers, visceral fat responds favorably to good nutrition and regular exercise, so you can take steps to reduce the associated risk of chronic illness by:
Doing at least 150 minutes of moderate-intensity cardio exercise every week and muscle-strengthening exercises at least twice a week.
Eating foods that reduce inflammation, including vegetables, fruits, olive oils, seeds, nuts, fish, lean proteins, and other choices rich in antioxidants and fiber.
Engaging in stress-reducing exercises like yoga or meditation, which lowers the levels of cortisol in your blood. This hormone encourages the storage of visceral fat in your abdomen.
Encourage the white-to-beige transformation
While brown fat cells have naturally higher UCP1 levels than white and beige cells, research from the Dana-Farber Cancer Institute shows that we can potentially increase the release of the UCP1 protein from beige fat, effectively "browning" the cells and increasing their ability to burn calories. In rodent studies, an increase in a hormone called irisin amped up the production of this protein. The NIH-backed DFCI research found that exercising muscles releases irisin that triggers the UCP1 increase in beige cells, enhancing metabolism and effective energy use.
The resulting increase in your body's resting metabolic rate (RMR) means that you burn more calories while at rest. Your body needs more energy to function, which means your brown and beige fat cells work in overdrive to reduce the stores of white adipose tissue even when you are not actively engaged in exercise.
Fun fact: While we can control some aspects of our body composition, such as the percentage of fat and lean muscle mass, other elements are fixed. For example, women have higher body fat levels than men do, and genetics, hormones, and age also influence our body composition.
Boost brown fat cell levels
While the beige cell transformation has a positive health impact, brown fat might be even more important for obesity reduction. In 2014, Scientific American reported that brown fat cells can burn about 500 percent more stored energy than beige fat cells.
Humans are born with brown fat, but we can also develop "recruitable" brown fat cells by engaging in vigorous aerobic activity such as running or high-intensity interval training (HIIT). Research also suggests that exposure to temperatures lower than 66 degrees Fahrenheit for more than two hours a day can encourage brown fat development.
Capitalize on body composition
Body mass index (BMI) has long served as the standard to determine whether a person has a healthy weight for their height. However, a healthy BMI does not necessarily indicate a low level of body fat. In fact, someone who has extensive visceral fat stores may not have an unhealthy BMI or even appear overweight.
A body composition scan can help you find out exactly what makes up your physical form, including the amount of minerals, protein, and various types of fat. Instead of a simple body fat analysis, which only provides a body fat percentage, a DEXA scan distinguishes between essential and storage fat. The latter category is the white, brown, or beige adipose tissue we've been talking about all this time, while essential fat exists throughout the organs, bones, and tissues so the body systems can function as expected. The body burns storage fat for energy, not essential fat.
Fun fact: The functions of essential fat include heart and blood vessel health, vitamin absorption, and brain development. In fact, 60 percent of our gray matter is made up of fat cells!
A DEXA body composition scan detects visceral fat. An excess level of these white abdominal fat cells signals the need to revolutionize your health to avoid future wellness challenges. Knowing your numbers can help you return to the right path. If you're not sure where to start with wellness and feel discouraged, schedule a DEXA scan in your area to gain insight into your body composition, including fat levels.
References:
https://www.discovermagazine.com/health/whats-the-difference-between-white-fat-and-brown-fat
https://www.webmd.com/diet/brown-fat-what-you-need-to-know
https://www.mensjournal.com/health-fitness/everything-you-need-know-about-white-brown-and-beige-fat/
https://health.clevelandclinic.org/do-you-know-the-color-of-body-fat-infographic/
https://www.healthline.com/health/brown-fat#How-to-get-brown-fat
https://www.scientificamerican.com/article/supercharging-brown-fat-to-battle-obesity/
https://www.mensjournal.com/health-fitness/breathe-breathe-fat-out/
