Body Composition Test with DXA Scan and Goals
I went to the Body Composition Center in Redwood City, CA this week to get a DXA scan (formerly known as DEXA). This is a low-dose x-ray that can determine body mass. Here’s what the results looked like:
I had an evaluation using a different tool (the BodPod) in January 2011 which put me at 235lbs, 35% body fat, and 153lbs of lean body mass.
This week I was 218lbs, 27% body fat, and 158lbs of lean body mass. If these two evaluations can be accurately compared then I gained about 5 lbs of muscle and lost 20 lbs of fat. I am sure I lost more fat since I gained a good amount of weight after the 2011 scan was taken.
The DXA scan also gave me a bone density score (good) and a visceral fat score (also fine).
How is this useful information? It allows me to form clearer goals. For the sake of simplicity I’m assuming lean body does not change much during cutting.
Let me start with some extreme goals:
- 10% body fat at 175lbs – an end goal for the dieting I’ve been doing for the past 15 years
- 20% body fat at 213lbs – a likely impossible bulk to 171lbs of lean body mass, an idea of my natural maximum
- 10% body fat at 190lbs – again a cut back to 10%
I don’t always buy into calories-in calories-out hypothesis but it’s one way to set a goal. The generic Harris-Benedict BMR formula gives me that 2500 calories/day number. The more specific Katch-McArdle formula using lean body mass gives 2300 calories/day.
Let’s say I have a daily caloric need of 2300 cals and I can restrict myself to 1800 cals per day, that’s 1 pound a week.
So smaller, pretty realistic goals from 218 can be
- 8 weeks to 210 [3 weeks to 213 for this current DietBet that I’m participating in]
- 10 weeks to 200
- 10 weeks to 190
- 10 weeks to 180
- 5 weeks to 175
11 months to 10%.
For some context, the current dietbet takes me to 213 so if I can achieve that then 210 should be possible even with some stumbles.
Of course I’ve set goals like this before only to watch the near opposite happen.
- 8 weeks to 230
- 10 weeks to 240
- 10 weeks to 250
- 10 weeks to 260