I was walking through the gym today and noticed a chart of body fat by age and level of fitness, in categories like athlete, fitness, average and obese. I’m 66 years old and the chart stopped at 55, but I got the general message anyway. My trainer measures my body fat each month and it recently has been between 15 and 16%. So, extrapolating to my age, that probably puts me somewhere near the elderly athlete range.
This chart, from the American Council on Exercise published in 2009, starts by listing the % of fat termed “essential” for good health. For women, this number is higher and is impacted by breast mass and hormones not an issue in men, and seems to be required for a woman to normally ovulate.
Obesity is defined here by a body fat percentage of 25+% for men and >32% for women. You’ve probably heard the term Body Mass Index. BMI is a calculation based on your weight in Kg divided by the square of your height in Meters. BMI is often used as an estimate of levels of overweight and obesity. So, how do BMI and Body Fat percentages relate to one another? Poorly. My BMI is 26.7 which puts me in the category of overweight as its greater than 25. Yet by body fat percentage, my number is comparable to an elderly athlete.
To get a really accurate body fat measurement, you need to weigh yourself underwater or undergo body composition measurement utilizing the same xray technique used to assess for osteoporosis which requires getting irradiated. Neither are readily available. A good alternative is measurements of subcutaneous fat by an experienced person, usually a trainer, which is what my number is based on. A third and less accurate method is by electrical impedance via a scale or hand-held device.
So what’s the right amount of fat? First consider your age. If you’re young and active, the above “fitness” level for body fat is probably a good target. As you get older, say greater than 55 when the charts stop, realize that as we age, muscle mass declines and is replaced by fat. If you can keep in the average range, as listed above, you’re probably doing well. And for men, to get that “six pack,” you need to get down to about 8% body fat which puts you into the younger athlete category. Sounds like I’ll always be enjoying my smooth stomach!