Everything We Know About Body Fat
Everything We Know About Body Fat
Initially, it probably doesn’t seem like there’s much to body fat. It’s that shapeless irritating mass that hides your muscle, slows you down and is just generally the worst. Right?
Well… no. Not at all, actually. As it turns out, recent research has uncovered all sorts of fascinating aspects of this oft-maligned form of tissue. Understanding these findings can be useful in several ways. First, what we know about body fat could have a major impact on the way you go about trying to lose it – both via exercise and diet. But having a deeper understanding of fat may also impact how you see this particular aspect of your physique and, by extension, change your entire body image.
Just To Be Clear…
Before we dive into the science stuff, though, there are a few terms that need to be clarified.
Key to our discussion here is to be sure that we have a proper understanding of exactly what is meant by the word “fat,” which gets thrown around a lot – often incorrectly, as it turns out. In dietary vocabulary, fat (along with carbs and protein) refers to one of the three macronutrients that provide fuel to your body and are required in fairly large amounts to support life.
But this isn’t the type of fat that we’re talking about. Instead, we’re focused on body fat. More correctly called adipose tissue, this element of body composition is your body’s way of storing excess energy. Why does the distinction between dietary fat and adipose tissue matter? Because adipose tissue can be formed by extra calories from any macronutrient, not just fat.
Granted, it’s highly unusual for proteins to undergo this process and get packed away as adipose, but it does happen. Much more commonly, however, fast carbohydrates that far exceed an individual’s caloric needs get converted into triglycerides by the liver and tucked away as adipose somewhere. In the interest of responsible writing, however, it’s important to make this point absolutely clear: Carbohydrates are only stored as fat if they are absorbed quickly and are more than your body needs in the moment for fuel. Generally, a balanced diet and regular activity will minimize this effect.
Okay, so adipose tissue represents extra fuel, primarily derived from dietary fat but can also originate from carbs and even protein in some situations. But that’s not all.
Within the past several years, researchers have started to draw major distinctions between two very different forms of adipose. The most common type, white adipose, is stored under your skin (subcutaneous) or around your organs (visceral) and is what most people think of when they talk about body fat. White adipose, as mentioned, stores energy, provides warmth and protection and – as we’ll see later on – plays several other highly-influential roles within your body.
Found with far less frequency, brown adipose is actually largely responsible for burning calories to release heat. So, yes: This is a form of body fat that burns calories. Which is pretty awesome. Unfortunately, concentrations of brown adipose gradually decrease in the human body as we age. Interestingly, some research suggests that exercise and sleeping in a cold room – with the thermostat setting at about 66F – can both activate and increase your brown adipose.
But, really, that’s all there is to say about brown fat at this point. Since the chief concern for most people is the white stuff, any mention of “body fat” or “adipose” from here on out, will refer to white adipose.
What’s It Doing?
Interestingly, adipose tissue is not just the troublesome, amorphous glob of stored energy that people commonly assume. Instead, it’s a highly-active hormone secreting organ that has a pretty powerful influence over your overall health and metabolism. This influence is primarily exerted via three hormones – which, as a group, are known as adipokines.
The first, and likely more famous, of the adipokines is leptin. The focus of plenty of research and discussions as of late, this hormone plays a role in everything from growth to immune function and insulin sensitivity. Leptin’s claim to fame, however, has to do with it’s ability to control hunger cravings and, therefore, metabolism. When leptin levels pass a certain threshold, your brain senses that you have enough calories and can stop eating. You feel full.
The interesting thing, however, is that this system only works if your brain actually listens to leptin’s signals. If leptin levels remain elevated frequently and for long periods of time, your brain can get overwhelmed and start tuning leptin out. This has been repeatedly observed in obese individuals, suggesting that the entire hunger signal system is out of sync. At this point, though, it’s still unclear whether this state is caused by obesity or vice versa.
And then we have the adipokine adiponectin, which actually decreases as levels of adipose increase. This hormone is mainly focused on maintaining a healthy metabolism but also contributes to insulin sensitivity, inflammation control and cardiovascular health.
Finally, there’s visfatin – cleverly named for the fact that it’s produced in visceral fat (get it?!). First isolated relatively recently in 2005, research into the complex function of visfatin is still in the early stages with much left to be explained. While it does seem like visfatin could be useful in treating some obesity-related conditions like diabetes by mimicking the actions of insulin, it also encourages the growth of adipose. And that’s not so great.
A Word On Genetics
Clearly, then, there is a lot going on in that seemingly inactive adipose tissue that can have a pretty significant effect on your overall health and wellbeing. And, to be sure, much of the way our body processes fuel and reacts to hormone signals is predetermined by genetics. In fact, researchers in 2007 did identify a specific gene, known as FTO, that can predispose an individual to obesity and diabetes.
But, does that mean that our genes can completely doom us to obesity? Not according to a massive 2016 study that looked at the effects of regular exercise on 1280 people who all had this FTO gene. The team found that as little as 10 minutes each week of vigorous exercise was enough to help individual with FTO to lose weight and inches off their waistlines. If the subjects opted for moderate intensity exercise, though, at least 150 minutes was required each week for any noticeable change.
Okay, but why does any of this matter?
For one thing, adipose tissue is not the villain that it’s often made out to be. At proper levels, adipose actually plays several important roles – both structurally and chemically – within the body.
The research also suggests that obesity, even when it’s strongly linked with genetic influences, can be controlled. Granted, this will take considerable effort. Still, there is hope.