I have my first DXA scan and RMR scheduled for Thursday as a tool to get a baseline on body composition. My scale says I have a shockingly high BF% but I know those results are limited.
I started keto way of life 8 weeks ago and probably should have gotten one (and lab work) before I started but didn’t. What should I expect from my visit? I have a total knee replacement, too, and not sure if that will be problematic. THANKS!
Not sure what you’re looking for, so if I give too much info, or not enough, sorry!
My pre scan instructions indicated not to go in dehydrated or wearing any clothes with metal (for example, no zippers, but they didn’t make me take off my underwire bra 
). You’ll lay down face-up on a flat table, you may or may not fit within the confines of the equipment if you’re very large. They can adjust for this if needed (for example, rearrange you so your left arm is outside the scan, and interpolate that data using the info from your right arm). You’ll need to hold as still as possible during the scan. It’s very quick, just a few minutes, and quiet. No claustrophobia issues.
The place I went printed out a report with color pictures and went over the details and explained what each section meant. That took maybe 5 minutes. My report showed total body weight (which didn’t match my home scale), lean body weight in pounds (including bone and muscle, I believe), and total body fat by weight. It calculated my body fat percentage. Showed the same info by body part (trunk, left arm, right arm, left leg, right leg). A bone density report was included.
This was my baseline scan (sort of, after 50 lbs weight loss, still ~150 lbs to go; but prior to my first extended fast). The woman who helped me said that when I come in for a repeat scan, the future reports will show the change from baseline in these categories.
I’m really glad I did this, I got lots of useful informationand it will give me a way to empirically measure if I’m losing LBM with my diet and fasting.
Hope this information helps!
Edit: not sure about your knee replacement. Not a problem for the scan since I believe it’s essentially an X-ray. The texhnician may be able to tell you how that might affect your report.
I just finished my second DXA and first RMR. They are AMAZING! Call the facility for specifics about your knee. Wear comfy clothes, no zippers, jewelry, or anything. You also have to be completely fasted before the RMR scan, including no coffee or tea.
DXA takes about 10 min; RMR is longer (about 15); you’ll probably get your results right away.
I just found out that my RMR is 2059 calories per day, which means I have a fast metabolism. I was probably WAY undereating before keto; I was probably starving. I also learned than my body fat percentage has decreased, while my lean muscle mass has increased. My VAT issue has been cut in half.
When I had my first DEXA I also did the RMR and VO2max. If you aren,t doing the VO2max, which requires a treadmill run, you shouldn’t have to worry about your knee replacement. It’s an x-ray not a magnetic analysis. Although I believe knee replacements are made of non-magnetic material. I have pins in my arm from a work accident and they didn’t cause a problem. As far as what to expect… wear something comfy… i don’t remember if I disrobed to underwear or not. Lay down on a table while a device scans you from overhead (kind of like a flatbed image scanner in reverse). For the RMR, you wear a mask that measures the O2 and CO2 content of the air going in you and coming out of you. Seem to remember that took about 20 minutes.
Thank you. I am really looking forward to getting the baseline so I can get my BMR, add in exercise and see if there are any changes in a few months. I appreciate the information you gave.
Thank you. My knee is made of titanium (I believe). They had to use atypical parts because I am allergic to metals. Thanks for the information. I am a research analyst so really into data. Can’t wait to see the results.
One other quick bit of info. When they did my RMR they were also able to do a co2/o2 ratio analysis which tells them what you body is using primarily for fuel, carbs or fat. At the time the clinic had only been open for about 6 months and the technician was amazed at how far down the fat burning spectrum I was. He said it was the highest he had seen since they opened. this led to a discussion about my diet. At that point he told me that if I was keto adapted, for a guy my size it would make a fairly significant difference in the amount of LBM. Well he was right. I ate carbs for almost the next two weeks and went in for another scan and I had gained 13 pounds of lean body mass and reduced my body fat percentage by almost 2%. Not through any performance or effort on my own but by loading my muscles with water and glycogen.
Wow! Yes, I will be very interested to see if they can tell which fuel I use predominantly. I had to take a questionnaire and they asked about the type of diet/eating I did and why I wanted a scan so I filled them in on that. They asked a lot of other questions about mother’s familial heart disease and mother’s familial diabetes but they wouldn’t allow for selection of both father and mother, just father’s side, mother’s side, mother and grandmother, etc. it was odd. I will have to clarify my answers when I see them because There is T2 diabetes on both sides but I don’t have it and heart disease on both sides.
