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Saturday, 12 June 2010

Excuse me while I briefly slip into my white coat and end the % body fat discussion

Now that we have discussed % body fat ad nauseum (a subject I was previously nearly indifferent about), I feel it's my duty to at least outline some interesting facts I've learned over the past few days (I have to thank Danni, PubMed and my many wise readers for their assistance)


- DEXA scans are more accurate than TANITAs and they tend to read higher since they detect even very small areas of fat (a 10.9% reading, for example, on a TANITA may be a 14-15% on a DEXA, similarly a 30% on a TANITA, would likely be above the WHO "healthy" range on a more accurate DEXA)

- DEXA scans were used in the ONE study (Gallagher et al. Am J Clin Nut 2000; 72:694-701) the WHO based its guidelines on and may explain why the range is shifted higher than one might expect if one is measuring body fat with a TANITA.

- If the general population is going to use TANITAs, a "healthy" range based off of DEXAs should not be given as a reference

- TANITAs are also not very precise and fluctuate a lot in the course of a day

- No body fat % reading alone should be interpreted as healthy or unhealthy, but should be looked at in the context of the whole health picture of a person, ideally with the assistance of a physician versed in working with % body fat (okay, I think we all knew this one to begin with)

- After doing a thorough browse though research over PubMed, I can find no studies that directly correlate % body fat with health outcomes, so it's significance in overall health status and mortality has yet to be determined SO AGAIN the % alone, should be interpreted with caution and only in the context of many other health factors (exercise, BMI, diet, confounding health conditions, etc.)

After all this, I am left wondering what sort of helpful information one could get out of % body fat readings. Any thoughts readers? I have to say, I think most of us know before we step on a Tanita generally how healthy & fit we are and it is hard to think of a circumstance where it would add anything. Okay, end of discussion, I guess.

My next post might be about something interesting. But I'm not making any promises.

4 comments:

Danni said...

I've got nothing but have enjoyed this discussion. And I wasn't offended but probably a wee defensive. :-) Sorry 'bout that.

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Katie said...

I'm not sure how body fat percentage fits into overall health. Well, I have read that excess abdominal increases all kinds of health risks. And of course, if you don't have enough fat or you have too much fat it's harder to conceive...

Body fat percentage is generally interesting to note when you're an athlete. It does seem that elite athletes of various types of sports share similar body fat percentages.

Arcane said...

I've read that the numbers themselves don't mean anything, but rather it's the change in numbers over time which is illustrative. If you see the body fat drop sloly over time while you're weight stays relatively the same, it means you're getting healthier.