Are BMI guidelines for the birds?
Q. I recently read that the standard BMI calculation and guidelines aren't accurate for African-Americans and other ethniticies. Can you explain why and do you have recommendations for ethnic specific guidelines?
A. Your BMI, or body mass index, is nothing more than a way of expressing your weight in relation to your height. When we say that a BMI of between 19 and 25 is considered ideal, we're really just saying that for every height, there is a suggested healthy weight range. I'm 5'9" for example. The suggested healthy weight range for me is 128 to 169. (Click here to look up your BMI)
I think you're probably referring to a recent article in the British Journal of Nutrition (reported in the Washington Post), which points out that the BMI guidelines are based on statistics gathered in a predominantly Caucasian population.
Because of differences in average bone density, lean muscle mass, and so on, the BMI guidelines may be misleading for non-Caucasians. For example, it might underestimate healthy weight range for some people of African descent and overestimate the range for some of Asian descent. Even for Caucasians, though, the BMI is a fairly crude gauge of body composition. For example, it's not a good guide for athletes, who have more muscle mass, or for the elderly, who have lost muscle and bone mass.
The BMI guidelines are supposed is to help identify people who may have too much (or too little) body fat. Other ways to gauge whether you are carrying around an unhealthy amount of fat include:
Have a fitness trainer measure your body fat percentage. The recommended percentage depends on your age and gender but as a very general guideline, women should try to keep body fat under 30% and men under 25%. There are several methods of measuring body fat. The most accurate is also the least convenient: It involves being submerged in a tank of water. A fitness trainer can get a pretty good estimate using body fat calipers--but good training and technique are essential. Those scales and hand-held devices that calculate body fat by measuring electrical impedance are notoriously inaccurate.
Measure your waist size. A waist measurement of more than 35" for women or 40" for men increases your risk of heart disease and other diseases.
Calculate your waist-to-height ratio by dividing your waist measurement by your height. If you are 5'5" and your waist measures 32", your ratio would be 32/65 or 0.49. A ratio of less than 0.50 is considered healthy.
Calculate your waist-to-hip ratio by dividing your waist measurement by your hip measurement. If your waist measures 32" and your hips measure 38", your ratio would be 32/38 or 0.84. As a general rule, women are shooting for a ratio of less than 0.8 and guys for a ratio of 0.95 or less.
Ask your physician for individual guidance. Your physician sees the whole you, not just a single measurement or statistic. If you're not sure whether your weight is healthy or not, ask your health care provider for input.
 older posts |
home | newer posts  |
| Manufacturers replacing high fructose corn syrup with sugar. Big deal. | | Nutrition Data Blog | | New devices measure your metabolism, but how accurate are they? |
Posted by: Caroline | Aug 28, 2009 7:32:02 PM
I want to invite everyone to the DC VegFest, a celebration of the best of all that is vegetarian in Washington, DC.
It will feature tasty, nutritious food; food prep demos; informative talks; an array of exhibitors and vendors; free goodie bags to the first 400 visitors; and more! Hope to see you there.
WHERE: University Yard at 2000 blk H St., N.W., Washington, D.C. 20052
WHEN: Saturday, September 12, 2009
12 p.m. to 6 p.m.
ORGANIZED BY: Compassion Over Killing and the Vegetarian Society of D.C.
Posted by: Ginger | Jul 9, 2009 11:03:25 AM
I clicked on a link that was supposed to have info on healthy eating for pg women. I think something is wrong with the link.
Monica's Response: We just updated this feature slot on the homepage. Maybe you clicked JUST as we were updating? In any case, here's the post you were looking for: http://blog.nutritiondata.com/ndblog/2009/06/how-much-protein-for-a-healthy-pregancy.html
Also, use the search box on the right hand side of the page to search for other blog posts on pregnancy.
Posted by: James | Jul 6, 2009 11:52:39 PM
Seems like if you have to measure all these ratios, you are not paying attention to your mirror. Do you look fit and trim? And how is your nutrition? Are you eating primarily healthy food and exercising? If yes, you are probably fine, no matter what nationality. I eat primarily raw vegan exercise, and drink plenty of water. I've never gotten measured for bodyfat percentage, but am sure I am OK at 5'10 and 155 lbs.
James Reno (editor)
www.Raw-Food-Repair.com
Posted by: Riz Din | Jun 29, 2009 6:57:47 PM
I like Monica's approach to use what I call the holy trinity of health measures (BMI, body fat, hip to waist ratio). I don't know all that much about health/nutrition but I try to keep an eye on these measures.
I recently bought a body fat monitor (Omron brand), which is hand held. It's quite cheap and pretty useful if you take an average of two or three readings, just make sure to take measurements at the same time each day. Agree that accuracy is not to be relied upon as 80% but it seems about 90% right and more importantly the monitor is fairly consistent and so can be used to compare body fat changes over months and years.
Posted by: fat preacher | Jun 27, 2009 4:24:58 AM
Monica, you continue to impress me with your sensible and practical posts!
I recently had a bone density test. Although the primary idea is to check for bone density (duh!), it also give you a complete breakdown of your body composition: Fat, lean, bone.
You can't do this every week, to be sure. But, it gives you a good idea of where you are at in terms of an very accurate and objective standard. From there, you can use other methods to keep track of your present condition.
Personally, I use the one site Accu-Measure caliper. It may not give the best absolute measurement, but it is very good for tracking progress.
Keep up the good posts, good advice and great tips!
