12 Enlightening Facts About Body Fat


The human body is an amazing thing. For each one of us, it’s the most intimate object we know. And yet most of us don’t know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

Let’s face it: Fat gets a bad rap. Entire industries have been built upon the criticism and attempted reduction of body fat. But fat, formally known as adipose tissue, is a crucial part of your hormonal and metabolic processes. Adipose tissue is a major site of energy storage, and has a key role in the regulation of metabolism and insulin production in your body—not to mention, it helps keep you warm. Having too much fat can be a bad thing, but having too little can pose problems as well.

Fat is stored in the body in the form of triglycerides, free fatty acid (FFA) molecules that are held together by a molecule called glycerol, a type of alcohol. Most of our body fat is stored in fat cells called adipocytes, but fat can also be stored as droplets within skeletal muscle cells. In addition, some triglycerides even roam freely in your blood stream. (These are the ones most easily broken down through exercise.)

Before you demonize fat, take a look at these 12 facts about your adipose tissue.


Your fat is not just a layer of padding—it’s actually an organ of the endocrine system. “Fat secretes a lot of hormones, while activating or deactivating many more,” Indraneil Mukherjee, a doctor at The Southeastern Center for Digestive Disorders and Pancreatic Cancer, Florida, tells Mental Floss. It’s comprised of adipocytes and fat cell types called the stroma-vascular fraction, which are made up of growth factors—messengers the body uses to signal cells—as well as stem cells, blood cells, and a host of other cell types.


Adipose tissue is “a metabolically dynamic organ,” according to a study in Archives of Medical Science, whose primary job is to store excess energy. It also synthesizes “a number of biologically active compounds that regulate metabolic homeostasis.” In other words, it controls your body’s energy balance by regulating appetite signals from the central nervous system and metabolic activity in peripheral tissues. Chronic over-nutrition—eating too much on a regular basis—can cause inflammatory responses and metabolic disorders that can lead to disease: most obviously, obesity.


White adipose tissue stores your body’s reserves of energy, and the endocrine cells mentioned above, which secrete crucial hormones and molecules. There are even “adipose depots” where white adipose tissue tends to gather more easily, located around organs such as the heart, lung, and kidney.


Brown adipose tissue is typically found in newborn human babies and hibernating mammals, according to a study in Frontiers in Endocrinology. Its main function is to generate heat—keeping you warm—and to do so, it contains more mitochondria and capillaries than white adipose tissue.

Up until recently, researchers weren’t sure brown fat existed in adults. “There's a lot of excitement around the discovery,” Yi Sherry Zhang, an assistant professor at the TOPS Obesity and Metabolic Research Center at the Medical College of Wisconsin, tells Mental Floss. “It helps to regulate energy expenditure. This is important because drugs that target this type of fat may provide a new way to treat obesity.”


While it is now commonly known that obesity—when a person carries more weight than is considered healthy for their height—can predispose a person to type 2 diabetes, too little fat has a similar effect, according to the American Diabetes Association. Type 2 diabetes is a group of diseases in which the body has an impaired ability to produce or respond to the hormone insulin. And it turns out having too little fat is due in part to a lack of a lipid-storing “compartments,” which leads to an imbalance of triglyceride and free fatty acid levels, leading to insulin resistance.


Researchers at McMaster University have begun studying a new realm of therapies known as postbiotics, the by-products that bacteria leave behind, which help the body synthesize insulin more effectively. In a new study, scientists discovered that administering postbiotics to mice with obesity reduced their insulin sensitivity—without any need for weight loss—heralding promising potential treatments for obesity with type 2 diabetes.


Adipose tissue also secrets “hormones that make cancer cells grow quicker,” says Mukherjee. In fact, when adipose tissue expands, it also allows more immune cells to enter the tissue. These B and T immune cells secrete pro-inflammatory molecules such as adipokines [PDF]—peptides that signal other organs—and cytokines, which create the perfect microenvironment for tumor growth, according to a study in Frontiers in Physiology.


If you are so inclined, Mukherjee points out that “fat transplant is legal”—so you can technically surgically move it from one body part to another without any harm done, “for vanity,” he says. These so-called fat transfers can augment a formerly flat part of your body, but buyer beware—not only can you experience the side effects of surgery such as swelling, bruising, several weeks of recovery time, you can develop lumps.


The number of your fat cells can increase, but once the cellular structures have developed, they never go away. “With dieting, they just get smaller,” Mukherjee says. Zhang adds, “Each of us has 10 billion to 30 billion fat cells in our body.” Obese people can eventually have up to 100 billion fat cells.


It does so by sending out small molecules called microRNAs (miRNAs) that control gene activity, according to a study in Nature. After injecting genetically modified mice with fluorescent liver cell miRnas, researchers saw a significant drop in liver cell fluorescence, which suggested that the fat tissue was communicating with the liver to regulate gene expression. They hope to further study this process to discover new treatment methods for obesity and type 2 diabetes.


“We are beginning to understand the genetic basis for fat distribution and obesity,” says Zhang. “We have recently published genes that play a role in determining how body fat is distributed,” she continues. She hopes that these discoveries will help researchers understand the genetic component of common disorders like metabolic syndrome, type 2 diabetes, and obesity.


Researchers studying fat to better understand metabolic disorders recently focused on the field of epigenetics, which is the study of “the various elements that regulate which genes are active in particular cells and how they are regulated,” Zhang says. She believes that epigenetic changes are likely to play a critical role in the development of chronic disorders like metabolic syndrome and type 2 diabetes. “Unlike the genetic code, it is possible to reverse and alter these elements, which means we can potentially develop new ways to prevent and treat these common disorders.”

12 Creative Ways to Spend Your FSA Money Before the Deadline

stockfour/iStock via Getty Images
stockfour/iStock via Getty Images

If you have a Flexible Spending Account (FSA), chances are, time is running out for you to use that cash. Depending on your employer’s rules, if you don’t spend your FSA money by the end of the grace period, you potentially lose some of it. Lost cash is never a good thing.

For those unfamiliar, an FSA is an employer-sponsored spending account. You deposit pre-tax dollars into the account, and you can spend that money on a number of health care expenses. It’s kind of like a Health Savings Account (HSA), but with a few big differences—namely, your HSA funds roll over from year to year, so there’s no deadline to spend it all. With an FSA, though, most of your funds expire at the end of the year. Bummer.

The good news is: The law allows employers to roll $500 over into the new year and also offer a grace period of up to two and a half months to use that cash (March 15). Depending on your employer, you might not even have that long, though. The deadline is fast approaching for many account holders, so if you have to use your FSA money soon, here are a handful of creative ways to spend it.

1. Buy some new shades.

Head to the optometrist, get an eye prescription, then use your FSA funds to buy some new specs or shades. Contact lenses and solution are also covered.

You can also buy reading glasses with your FSA money, and you don’t even need a prescription.

2. Try acupuncture.

Scientists are divided on the efficacy of acupuncture, but some studies show it’s useful for treating chronic pain, arthritis, and even depression. If you’ve been curious about the treatment, now's a good time to try it: Your FSA money will cover acupuncture sessions in some cases. You can even buy an acupressure mat without a prescription.

If you’d rather go to a chiropractor, your FSA funds cover those visits, too.

3. Stock up on staples.

If you’re running low on standard over-the-counter meds, good news: Most of them are FSA-eligible. This includes headache medicine, pain relievers, antacids, heartburn meds, and anything else your heart (or other parts of your body) desires.

There’s one big caveat, though: Most of these require a prescription in order to be eligible, so you may have to make an appointment with your doctor first. The FSA store tells you which over-the-counter items require a prescription.

4. Treat your feet.

Give your feet a break with a pair of massaging gel shoe inserts. They’re FSA-eligible, along with a few other foot care products, including arch braces, toe cushions, and callus trimmers.

In some cases, foot massagers or circulators may be covered, too. For example, here’s one that’s available via the FSA store, no prescription necessary.

5. Get clear skin.

Yep—acne treatments, toner, and other skin care products are all eligible for FSA spending. Again, most of these require a prescription for reimbursement, but don’t let that deter you. Your doctor is familiar with the rules and you shouldn’t have trouble getting a prescription. And, as WageWorks points out, your prescription also lasts for a year. Check the rules of your FSA plan to see if you need a separate prescription for each item, or if you can include multiple products or drug categories on a single prescription.

While we’re on the topic of faces, lip balm is another great way to spend your FSA funds—and you don’t need a prescription for that. There’s also no prescription necessary for this vibrating face massager.

6. Fill your medicine cabinet.

If your medicine cabinet is getting bare, or you don’t have one to begin with, stock it with a handful of FSA-eligible items. Here are some items that don’t require a prescription:

You can also stock up on first aid kits. You don’t need a prescription to buy those, and many of them come with pain relievers and other medicine.

7. Make sure you’re covered in the bedroom.

Condoms are FSA-eligible, and so are pregnancy tests, monitors, and fertility kits. Female contraceptives are also covered when you have a prescription.

8. Prepare for your upcoming vacation.

If you have a vacation planned this year, use your FSA money to stock up on trip essentials. For example:

9. Get a better night’s sleep.

If you have trouble sleeping, sleep aids are eligible, though you’ll need a prescription. If you want to try a sleep mask, many of them are eligible without a prescription. For example, there’s this relaxing sleep mask and this thermal eye mask.

For those nights you’re sleeping off a cold or flu, a vaporizer can make a big difference, and those are eligible, too (no prescription required). Bed warmers like this one are often covered, too.

Your FSA funds likely cover more than you realize, so if you have to use them up by the deadline, get creative. This list should help you get started, and many drugstores will tell you which items are FSA-eligible when you shop online.

10. Go to the dentist.

While basics like toothpaste and cosmetic procedures like whitening treatments aren’t FSA eligible, most of the expenses you incur at your dentist’s office are. That includes co-pays and deductibles as well as fees for cleanings, x-rays, fillings, and even the cost of braces. There are also some products you can buy over-the-counter without ever visiting the dentist. Some mouthguards that prevent you from grinding your teeth at night are eligible, as are cleaning solutions for retainers and dentures.

11. Try some new gadgets.

If you still have some extra cash to burn, it’s a great time to try some expensive high-tech devices that you’ve been curious about but might not otherwise want to splurge on. The list includes light therapy treatments for acne, vibrating nausea relief bands, electrical stimulation devices for chronic pain, cloud-connected stethoscopes, and smart thermometers.

12. Head to Amazon.

There are plenty of FSA-eligible items available on Amazon, including items for foot health, cold and allergy medication, eye care, and first-aid kits. Find out more details on how to spend your FSA money on Amazon here.

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30 Pungent Facts About Farts

This man is clearly not trying to hide the fact he just passed gas.
This man is clearly not trying to hide the fact he just passed gas.
BrilliantEye/iStock via Getty Images

Whether you openly admit it or desperately try to hide it, it’s an undeniable fact that every living and breathing human being farts. And while passing what you thought was going to be silent gas only to be wrong in certain situations can definitely be embarrassing, there’s something undeniably humorous about flatulence—no matter your age.

If you do love a good fart joke, you’re in good company. The very first recorded joke, which was written by the Sumerians and dates all the way back to 1900 BCE, was about—you guessed it—breaking wind. And some of the world's great thinkers, from William Shakespeare to J.D. Salinger, have slipped a fart joke (or 10) into their work.

In this episode of The List Show, we're sniffing out 30 fascinating facts about farts—from why humans expel gas to how often the average adult squeezes the cheese. You can watch the full episode below.

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