In the fitness world there is an obsession with knowing one’s body fat percentage or BF %. Of course, knowing your numbers in any aspect of life is certainly better than blindly walking through the world with your head buried in the sand. However, I’m going to comment on what I believe is an unnecessary fixation on the BF% number. First, most of what follows will be a commentary on athletes. If you do not train in the gym towards a goal, then yes, you should probably take a keen interest in what your body fat percentage is. Moreover, if you are sedentary and do not exercise, or you do but still have a large amount of body fat around your midsection, it’s likely that you have an unhealthy amount of visceral fat around your organs, which is very dangerous. If you need a kick in the pants to get up off the couch and get moving, go test your BF % and work to decrease it. Good. I’m glad that’s out of the way. Now we can move on.
Also, there is value in knowing what your lean body mass is. If you are eating one gram of protein and carbohydrates per pound of bodyweight, you’re likely taking in too many calories. A better formula would be to eat based on what your lean body mass is (total weight minus body fat). So, if I weight 180 pounds, but my lean body mass is 165 pounds, I should be taking in nutrients based on 165 pounds. This is especially true if fat loss is your goal.
Okay, so you’ve gotten through the first part of this and you’re thinking, “Sean, I do train hard and I’m an athlete. Don’t I need to know my BF %?” My answer to that is no. Let me explain. As a trainer and health club owner, I see too many people become distracted by obtaining a lower BF % and I believe this is the wrong goal. For most cross fit athletes, MMA fighters and other professional sports, the amount of body fat one has is nearly irrelevant. What matters more is performance and the ability to produce on command. For this goal, you need to have a little body fat for the body to tap into for energy. If, on the other hand, an athlete becomes obsessed with some abstraction like BF%, his or her ability to perform will be hindered by an unneeded distraction about knowing a piece of information that will not help them.
It should also be noted that body types range widely from person to person. Some folks might walk around at 10% body fat and looked cut and jacked out of their mind simply because they hold fat in different places. I know guys with 15% body fat with incredible abs. The same goes for women. So, if your goal is purely aesthetic, and you train hard and are healthy, the mirror is a much better guide than a BF measurement. Again, some people are genetically predisposed to store more fat in their legs and glutes. Some people store it in their midsection. Where your body’s fat stores are has as much impact on how you look as your BF % does. Bottom line here, bodybuilders and physique competitors should let the mirror be their guide.
Another very important thing to remember about body fat testing is the inconsistency in which results occur. The method of testing–calipers, bioelectrical impedance, hydrostatic tanks–they all produce different results. Most bioelectrical impedance machines (the ones where you grab the metal parts and hold your arms out) are very unreliable and produce varying results hour to hour. This is especially true if you are well hydrated or have an increased intake in sodium. My wife and I competed in a bodybuilding and physique show and our coach, IFBB Pro Jon DeLaRosa (www.JonDelarosa.com), kept our sodium intake high throughout the entire contest prep. About three weeks into the prep, one of my employees at the gym wanted to test Holly’s body fat and the result from the machine was so ridiculous that it made me laugh. It didn’t make her laugh though. Despite having become significantly leaner, the machine had her at nearly 30 % body fat, reading as overweight/obese. I reassured her not to worry and explained how the reading was off. But, Holly was nearly de-railed by a piece of false information. She should have trusted the mirror and herself. Calipers and hydro tanks are more accurate, however, it’s worth repeating that your BF % may not have any relevance to you, depending on what your goals as an athlete are.
In closing, if you are an athlete, don’t focus on BF %. It’s a complete distraction to you and will hinder your ability to achieve your goals. If you are NOT an athlete and you know that you have a significant amount of fat to lose, or your gut is solid from too much visceral fat, then you should know your BF% number and work to decrease it via training hard and fueling your body with the proper nutrients based on your lean body mass, not your overall bodyweight. Again, the real takeaway here is that there is no cookie cutter approach or metric that can be applied to the whole population for anything in life. That includes ideal BF %, BMI, sodium intake, or anything else. Know thyself. Don’t be defined or distracted by a number!