We had a great time at TheFitExpo Anaheim! It was a really busy two days down at the Anaheim Convention Center, but we had a great time meeting a lot of fitness enthusiasts and professionals and allowing them to experience one of our professional models, the InBody 570.
On those two days, we tested the body compositions of 402 people. When we looked at the data this, we found some interesting trends with respect to BMI and body fat percentage. The results may surprise you.
BMI vs. Body Fat Percentage
When examining at the results, we looked mainly at the discrepancy between how someone using a BMI table would categorize a person vs. using body fat percentage markers.
For BMI, we used the ranges set by the World Health Organization, which begins the “normal range” at 18.50 and “overweight/pre-obese” at 25.
Unlike BMI, there are different ranges for body compositions for men and women. When it comes to body fat, what’s considered “healthy” or “normal” really depends on whom you ask. For example:
The American College of Sports Medicine (ACSM) ranges for “satisfactory, good health”:
- Men: 10-22%
- Women: 20-32%
The American Council of Exercise ranges for non-athletes:
- Men: 14-24%
- Women: 21-31%
The ranges we use to assess people are actually somewhat stricter for both men and women, and are based on the ideal body fat percentage (15% for men, 23% for women) as described by both Lohman in Advances In Body Composition Assessment and Lee and Nieman in Nutritional Assessment. From those two figures, we created a 10% range by creating a ±5% window. Our ranges are:
- Men: 10-20%
- Women: 18-28%
These are the ranges that appeared on our result sheets and the ones we will be using when looking at the data.
Of the 402 people who tested, 235 (58.4%) were male and 167 (41.6%) were female, with an average age of 29. The youngest person we tested was 6.5 and the oldest was 69.
The attendees at TheFitExpo were skewed towards being fit and lean. As a result, we tested some very fit people. The leanest man had a body composition of 5.1%, with a BMI of 25.8. The leanest woman we tested had a body fat percentage of 10% with a BMI of 21.
Because BMI does not take gender or age into account, we were able to calculate the average BMI for those who tested: 24.825. This is just under what the WHO considers pre-obese.
When looking at the overall population – which is what BMI is intended to be used for – a case could be made that the population we tested was verging on becoming overweight. When we compared the BMI results against the body fat percentages, however, we found that this assumption is flawed, especially when looking at the results for the men.
For men, the average BMI was 25.87 (overweight/pre-obese). However, the average body fat percentage was 16.75%. This is quite close to the ideal body fat percentage and well within the healthy range, even by our strict standards.
When we drilled down the population by subgrouping the men into body fat percentage ranges, we found some even more interesting results.
As might be expected, as body fat ranges increase, as does BMI. What was very interesting, however, was that men who had body fat percentages in the healthy range – between 10% and 20% – were consistently misjudged by BMI as being overweight and/or pre-obese.
This disagreement between BMI and body fat percentage can be very frustrating for these men if they are being held accountable by a group, such as an insurance company, that bases assumption about weight on BMI results. We found that BMI actually reported some men as obese when they were in fact very lean; we tested one man with a BMI of 30.8 but a body fat percentage of 12.8%
The population of women that we tested was less lean than men, with an average body fat percentage of 27.38%. This is just under where we begin designating women as “overfat.” The average BMI was 23.78. Here’s what we found when we drilled down by subgroups:
In women, we found that body fat percentage ranges and BMI ranges agreed in their assessments of people’s weight. Overweight/pre-obese designations did not begin until body fat percentages rose above 28% – a marker of being overfat by our standards.
Because the average body fat percentage for the group of women was nearly at the overfat range, the correlation between body fat percentage and BMI was higher than it was for men. The men were much leaner as a group and were much more susceptible to being misjudged by BMI, particularly the group that maintained a healthy body fat percentage.
From what we observed from the results, as you become leaner, BMI becomes less relevant and less useful as a method of assessing body weight.
About Age Being a Factor In Fat Gain…
One common thing we heard over the weekend was people saying that because they were a bit older (and this ranged quite a bit) that they had put on some extra fat.
While it may be true that older people might have more fat mass than younger people, this is potentially due to a long life lived with unhealthy habits leading to fat accumulation over time.
We have always maintained that age should not be taken into account when assessing body composition, which is why unlike other tools such as skinfold calipers, our devices do not use any empirical adjustments based upon age. Below is the reason why:
Despite being 65 years old, this person* had a body fat percentage of 13.7%. These results clearly show that age does not necessarily condemn a person to extra fat mass or the loss of Lean Body Mass. With proper exercise and diet, these results indicate that it is possible to maintain a healthy body composition as you age, even as you approach your 70s.
Were you at this year’s TheFitExpo? Did you get your body composition tested? Let us know what you think on our Facebook page, we’d love to hear from you! You can also watch our recap video below to see what people were saying at our booth at TheFitExpo!