I think I can officially now say that I’m definitely skinny fat. And, Shannon, at least part of it was definitely worse than I expected!
Friday was the day that I was having Resting Metabolic Testing (RMR) and Body Fat testing using the Bod Pod.
Resting Metabolic Rate Testing
RMR tells you what calories you burn just existing, without doing anything. The linked article says that there are two ways to calculate RMR. One way is to use various formulas based upon things like height and weight while some include body fat. The other way is to use indirect calorimetry which uses your expired gases to calculate the fuel being used and then to convert that information to calculate the number of calories burned. That was the type of test I had.
I had a long list of instructions. I couldn’t eat or drink anything other than water for at least 4 hours before the test. I couldn’t exercise at least 4 hours before the test. There was a restriction on taking anything with pseudoephedrine or caffeine for at least 4 hours before the test. I also found a web site which said it was best to not exercise for 12 to 24 hours before the test, so I skipped my Thursday exercise.
When I went in to have the test, I was given something to clip on my nose so I could only breathe through my mouth, then I had to breathe naturally into the device:
This was sort of a weird feeling. I was given napkins, because the person administering the test told me that toward the end I would actually drool (yuck!). I sat there quietly just breathing and it actually was over more quickly than I expected. The result was: 1120 calories RMR.
To put in perspective, the Mifflin-St Jeor formula used by Fitbit gives me an RMR of 1224. So, not even counting any other activity during the day, Fitbit is already overestimating the calories I burn by at least 104 calories a day. The guy administering the test did stress to me that lots of things can affect RMR, so what Fitbit gives is not exact and is an estimate. For example, the things I couldn’t do for 4 hours before the test (eat, exercise, take caffeine and so on) are all things that can increase metabolic rate.
I’ve often posted here that my actual weight loss has generally been less than what I might expect from my Fitbit calorie deficit. Some of that, I’m sure, is because the food calories eaten are not exact — I doubt restaurants carefully measure ingredients to match calorie counts on a website and while I weigh my food most of the time, I know I’m not perfect either.
Still, I had the feeling that my RMR was just not the 1224 Fitbit predicts. And, it isn’t. What that means is that my RMR is about 91.5% of what Fitbit says. So, what I want to do is lower the calorie burn Fitbit gives me by 8.5% to get something that might be more accurate. I know it won’t be exact, but I am hoping that would be more accurate. The other day Fitbit said I burned 1692 calories and I had a deficit of 284 calories for the day. If I adjust that down by 8.5%, I get a burn of 1548 calories which reduces my calorie deficit to 108 calories. And, the difference adds up. Last month Fitbit said I burned an average of 1449 calories a day (yes, I know that was low). But, reducing it 8.5%, I get an average calorie burn of 1326 calories. So, my deficit of 166 calories a day suddenly becomes 43 calories a day.
The problem is that Fitbit, though, won’t let you set a custom RMR. You have to use their formula. But, there is a work around to trick Fitbit into changing your RMR which I got from the linked article. Basically I changed my age and height on Fitbit until the formula gave me an RMR of 1121 (the closest I could manage to 1120). Basically Fitbit now thinks I am several years older and 4 inches shorter, but my RMR is now correct and I should get a more accurate, albeit it more depressing, calorie burn number.
It is sort of sad to realize that on a day when I thought I was burning about 1700 calories, I was really only burning 1550 calories. But, that is the reality and I need to know that so that I have a better idea of what I need to do to either lose weight or maintain weight loss.
Oh – I paid $75 for the RMR testing which seems fair given the time it took to do it.
Body Fat Testing – Bod Pod
Once the RMR testing was over, I headed over to have my body fat tested using the Bod Pod. That is kind of a cutesy name, but it is actually pretty accurate. Herewith the Bod Pod:
This is actually a pretty simple test. You just sit in the Bod Pod for about 45 seconds and that’s it. First, though, I had to change clothes. The instructions are to either wear a swimsuit or a sports bra and tight shorts. I ended up wearing a sports bra and swimsuit bottoms. I didn’t wear the entire swimsuit as a website I read said to wear a tight Spandex suit or a sports bra and compression shorts. I didn’t have a tight suit. The link isn’t to where I went but it had more detailed instructions that I got. I didn’t think about it at the time, but I hope what I wore was tight enough. The sports bra was fine, but the swimsuit bottoms were kind of lose. I bought them as part of a swimsuit with a loose top (which is why I didn’t use it) and regular two piece bottoms. However, I bought them 50 pounds or so ago so they were kind of loose. I wish I had thought to ask, but if they weren’t OK I guess the person testing me would have said something.
Anyway, I also had to wear a swim cap and then I just sat in the Bod Pod. It was a little cold inside, but not too bad. He ran it for about 45 seconds, opened the door, then ran it a second time and we were done. The Bod Pod testing cost $50. There are some mobile Bod Pods that I think are a little cheaper, but this was easier than trying to chase down one of them.
OK, I’ve put it off long enough. I measured on my home scale before leaving and it said my body fat percentage was 38%. That is fairly typical over the last month or so. The highest was 39.25%. Of course, I knew that body fat scales are notoriously inaccurate. I didn’t expect mine to be off in my favor and was sort of expecting a result around 40%. Well, that turned out to be wildly optimistic.
The result was…. 45.3% body fat. That was fairly depressing. On the analysis I received, anything over 40% was considered risky and from 30.1% to 40% was excess fat. For me, my first goal has been to get to 35%, as some consider that to be the critical number of older women. Getting to 30% seems a long way away.
The really difficult part is realizing that if I kept my lean body mass exactly the same — didn’t lose or gain — I would need to lose fat all the way down to about 124 pounds to get to 35% body fat. That is not a pretty thought. I have done it before, but it was really difficult and I didn’t sustain it.
I was actually going to talk in this post about what I plan to do and how this affects my goals. But, that is going to be long enough I’ll save it until later.
Oh, one thing was interesting. The Bod Pod analysis gave me an estimated RMR of 1069 calories which was based upon the information from the Bod Pod. The good news is that the tester said that my RMR result of 1120 was more accurate as it was actually measured while the Bod Pod was an estimate. So, from that standpoint, at least something went good. I’m glad I sprang for the RMR testing. One place I called just offered the RMR from the Bod Pod and I can see that kind of estimate is not as accurate as actually doing the breathing test.
While I’m not happy about the body fat number, I realize that it is what it is and not knowing doesn’t change that. I might like thinking it was 38%, but that isn’t accurate and it is better to know real numbers than fake numbers. I still think the body fat percentage my scale gives me is of some value as I’ve seen it come down a lot while losing weight. So, I think the relative improvement has been shown to me, but this probably means I started out with a much higher body percentage than I realized.
More later about where I go from here.