Our Misconceptions about Body Fat Run Deep
Popular culture, social standards of beauty, and the media’s incessant message of thinner, thinner, thinner, have all skewed our perception of body fat. We are far more likely to associate our body fat with the way we look than the way we feel or how healthy we are. And the message that being thin automatically makes you healthy and being overweight automatically makes you unhealthy is just plain wrong. Now don’t misunderstand me, body fat can be a healthy or unhealthy organ depending on many factors, like any other organ or system in your body. If you’re at the extreme ends of the body fat spectrum, either too low or too high, there will be serious health consequences but the data is a little surprising for those in the middle.
The Obesity Paradox
Have you ever heard of the obesity paradox? Well, if not let me tell you that it’s one of the hottest topics in health today. Study results of the correlation of BMI (body mass index) and all cause mortality didn’t yield the expected results. In fact, the results were quite surprising and hint at the complex nature of body fat. Individuals with very low BMI scores, the underweight, had the lowest survival rates, followed by those individuals with very high BMI scores, the severely obese. Here’s where the real surprise came in…individuals in the overweight and mild to moderate obese categories actually had similar, and in some cases better survival rates than those with normal BMI scores.
What the research data tells us is that having too much body fat puts us at risk for certain diseases like diabetes, cardiovascular disease, and some cancers but being overweight or mild to moderately obese can be protective, increasing overall survival rates. Another conundrum is the fact that many obese individuals never develop the predicted metabolic diseases, like diabetes, expected based on their BMI scores (and other measurements). See the paradox? Now keep in mind that these studies on the BMI-all cause mortality relationships are hotly debated. Let me tell you how I see it from my scientific perspective and what it means for your health.
Body Fat Defined
Once considered just a repository for extra calories, we now know that body fat or adipose tissue plays a much bigger role in our health. Adipose tissue is a complex organ that stores extra energy, regulates metabolism, influences hormones and vascular function, and modulates the immune system. Think about this for a minute. I mean this is pretty remarkable! And it gives you a pretty strong insight into the powerful role body fat plays in our health. While we typically think of fat as one specific thing, it’s really a complex organ comprised of different kinds fat with different functions. For example there’s brown, white, and beige fat and fat that resides under your skin called subcutaneous fat and fat that resides within your abdomen and around your organs called visceral fat. All of these different kinds of fat function differently and each influences the function of the others and your health in general.
Having different kinds and amounts of body fat will contribute to your health state. Small or moderate amounts of subcutaneous white fat, often called lean fat (ironic right?), seem to have benefits while having large amounts of visceral fat is associated with increased inflammation and disease risks. Another example is brown fat. This is the calorie burning body fat that generates heat. As adults we have very little, if any. What we have instead is beige fat. Beige fat comes from the same cells that would become white fat but instead, have been stimulated by cold (and sometimes other factors) to behave like brown fat. These calorie-guzzling cells increase our metabolism.
Body Fat and Your Health
Back to the obesity paradox and your health. What makes a significant difference to your health is how much fat you have and of what types. Using BMI (body mass index) as a measure of obesity doesn’t inform about body composition. For example, an individual in an obese category based on BMI could have a body fat percentage ranging from 5%-30% or more! In addition, BMI tells us nothing about how much of each type of body fat an individual may have. Finally, because body fat, regardless of type, is integrated into the immune, endocrine, and metabolic systems, lifestyle habits like diet, stress, and exercise, along with your genetics, medical conditions and therapies, can all influence the function of the fat you have.
So what do you do? First, don’t make assumptions about your health based on the scale or your BMI, they’re not an accurate reflection of the complex functions of your body fat and therefore your health. Second, don’t assume just because you’re “thin” you’re automatically healthy. Having the wrong kind of fat can make you unhealthy. And finally, lifestyle habits play an essential role in developing and maintaining healthy fat. These habits shouldn’t come as any surprise to you, they’re the same habits that protect you from disease and help you live a healthy life. They include eating a healthy diet, exercising regularly, managing your stress, and sleeping well. If you’re eating a diet high in added sugar and lots of processed foods, I can tell you your body fat is not likely to be doing you any favors. The same is going to be true if you’re sitting around a lot, regularly sleeping poorly, and are overwhelmed by stress.
Knowing When it’s Too Much
Now the data related to the obesity paradox does not give you an excuse to go crazy and put on weight. However, if you’re lifestyle habits are pretty good, and you have normal blood pressure levels and a healthy lipid panel you may not need to worry about the extra weight. And if you are overweight because your lifestyle habits aren’t so good, don’t think that you won’t be healthy until you reach a certain “goal” weight. As soon as you start making healthy choices your body will respond. We can’t easily measure these responses (unless you have a research lab!) so we typically turn to the scale to mark our progress. But let me tell you as a trained cell and molecular scientist your body is responding and making positive changes as soon as you down that broccoli or go for a walk!
We aren’t yet at a place where we can easily measure the types of body fat an individual has and what kinds of positive or negative functions it might be carrying out. So physicians are still going to recommend that you lose the weight. The idea is that if you lose weight, you lessen the impact of any negative functions associated with having too much of one type of fat. In addition to this, when people lose weight they generally adopt healthier lifestyle habits. But beware! Remember, you can be unhealthy at any weight if you’re making poor lifestyle choices.
What’s the answer? Worry less about achieving a specific weight and more about living a healthy lifestyle. Thinking “what will make me healthy” will serve you and your health far more than than thinking “how many calories does that have.”
Until next time, stay well!
Dr. Tobi Schmidt