13 Weeks: Tool Time

Week 9 of my second 13 week season: low carb diet and more exercise, tracking my weight, blood glucose, and body fat. You can follow me at my 13 Weeks Facebook page for daily updates, and you can join Fitocracy (free!) and follow my daily exercise, and maybe even start tracking your own.

When I started off on this second 13 week experiment, I decided I was going to emphasize losing body fat as well as glucose -- and yes, my weight, I just can't resist. There are a lot of ways in which we can measure body fat.

You can measure your waist and neck size and apply an empirical formula. This is the method the Army uses, and studies have shown it's reasonably accurate.

You can take skinfold measurements with a calipers, and compute the result with a different empirical formula. This is a bit more accurate than the Army method (although not much).

You can have your body density measured by weighing yourself, and weighing yourself totally immersed under water. This is the "gold standard" method medically, but it's not very practical at home.

You can go to a radiologist and have body composition measured by taking a full-body X-ray. This is called DXA body composition. (The link is to the radiology practice of which PJM contributor Paul Hsieh is a member. Just a random plug.) This method is very good but has several disadvantages: you certainly can't do it at home, it means making an appointment and getting the full-body X-ray done, and it costs half a grand.  Or, 

You can use an impedance method device. This works by sending an alternating current through your body and measuring how the current flows. (I was going to write a description of what impedance is and how this works, but I kept falling asleep.) Never mind how it works, basically current flows more easily through muscle and bone than through fat, so the more fat you have the more you resist.

Here are the tools I've been using.