A reader made a comment after I posted the Motivation Station blog in which "Andy" is inspired to lower his BMI that the BMI is not a good representation of whether or not a person is healthy. As this was how the health and wellness program at Andy's office was measuring health, I didn't get into it then. However, now's the time to talk about (everyone's favorite subject...) BODY FAT!
So, as many of you may know, what the BMI (Body Mass Index) takes into account is two things: your height and your weight. That means that two people could have very similar BMIs but one of them could look skinny and muscular and the other could look flabby and out of shape. This is because it does not take into account the weight, or mass, of muscle. I still believe that for some people in the general population, the BMI can be a useful tool to help gauge whether or not they need to lose weight, but it is definitely not good for athletes to use.
Well, if the BMI is not going to work, how are you going to find out your body fat percentage? Good question. I realize that not everyone is enrolled in a nutrition class where they get to pinch their classmate's fat with a caliper (fun!). There are several ways that you can find out your body fat percentage. The most accessible way to people who don't have a caliper (and a person to skillfully utilize the caliper) is a bioelectrical impedance scale. Many scales on the market these days have this added feature; you need to stand on the scale with bare feet so that it can send a totally painless electrical current through your body to figure out how much fat is there versus water. Yes, there is a margin of error, and it does depend on how recently you have peed or had any water, but it can be a good way to figure out if you're carrying excess body fat. (You can also find a hand-held version that does not give your weight.)
How much is too much? It's different for men and women, but it is essential for men to have 3% body fat and for women to have 12% (essential meaning that health issues arise if it drops below). Women need more due to the whole child bearing thing. An athletic man should have 6-10% and an athletic female 10-15%. An ideal man, 11-14% and an ideal female, 16-23%. If a male has over 21% body fat he is overweight, for a woman it is 31%. Obese is over 25% for a man and 37% for a woman. Yes this skips over some numbers and no I'm not sure what it means if you're a woman and have between 23 and 31% body fat (like me!). I guess it means you should monitor your fat intake, get plenty of exercise, and aim to bring it down into the ideal range.
Remember, muscle burns fat. Don't let the number on a scale dictate what you eat or how much you exercise - that number is not taking into account your awesome, heavy muscles. Instead of being a slave to the scale, do plenty of strength-training to build those muscles, eat a healthy diet, and watch your percent body fat in order to gauge results.
I find the impedance scale useful, but my concern is that the commercially available ones with a reasonable price point (say less than $50) are probably not all that accurate. The accurate tools used by nutritionists cost several hundred dollars. The consumer grade scales tend to fluctuate a lot in both weight and body fat %.
ReplyDeleteGood article, Katrina -- there's a lot of debate on just how accurate the body fat analyzers are. Working at Healthworks with the handheld Omron analyzer, I've seen athletic women in the 15-23% much more often than the 12-15% fat range. In fact, only several very lean young 20s women had BF% in the low tees, and they were borderline underweight, not strong or healthy.
ReplyDeleteAnd that brings another point -- the older clients, ages 45-70, even very fit ones who strength train regularly, always test out higher on the body fat % Omron analyzer. I wonder if they're retaining water in some cases, or if the analyzer just doesn't account for age as well as it should. Or else we're all just getting older and fatter... but that can't be -- it's too depressing. And yet, we train on anyway to stem the tide of time!