For Leigh- Harris Benedict vs. Katch-Mcardle

[NHFLLC]

Hi Leigh,

I'm a trainer, just getting my legs underneath me in the business and was wondering why you prefer the Harris Benedict formula over the Katch-Mcardle (370+(21.6*lean mass in kg)) for body fat percentage measurement. Does the non-differential between men and women have something to do with it?

I would think that accounting for lean mass vs. total mass would be an important factor in determining BMR. But, then again, you have more experience than I; which is why I'm asking.

Care to enlighten me, please?

[LisaS]

I'm sure Leigh will answer for herself when she gets here - but my guess is that for an unknown population like someone reading her books since it is unlikely that they accurately know their LBM K-M would be a less universal formula for her to encourage the reader to use.

[Leigh P.]

Lisa nailed it.

In general though I think that with any vague formula it lands you at a estimate. I am sure lots of people here can attest to how varied daily caloric burn and activity can be, no formula will ever be able to nail that.

Take home points, formulas are nothing more than a jumping off point, for there you adjust as needed.

[John Izzo]

Personally, when I work with clients, I don't like the Harris-benedict formula. But I do tend to use the McArdle/Katch formula. Are they both estimates--of course they are. but when I deal with the general population, I like to have a starting point. That starting point begins with a bodyfat % assessment. (guys will use calipers, women will use Omron (if they are uncomfortable).
As Leigh stated, there are adjustments along the way. I usually begin with a food log and then measure up to the calorie need. is it an estimate? yep, but it gives me a shallow light on what adjustments
(+/-), the client needs to make in terms of diet. I think in terms of the general population, the McArdle /Katch is needed, because they are really going in blindly. Although, each formula you come across is not a means to an end.