Metabolism Test Today - BMR WAY low!

I found a place near my home that offers metabolic testing. There are two components to the test, one being a resting metabolic test, the other being an exercise test. Both together takes approximately 2 hours.

The resting test indicates what your metabolism is aka your basal metabolic rate (BMR). This is the number of calories your body needs to sustain its vital functions if you were to lie down all day. From this number as well as information regarding whether your calories are being burned from fat or carbs, they can make an action plan regarding your nutritional lifestyle. The exercise test is a VO2max test and it measures your cardio respiratory fitness level. They also take your fat burning efficiency into account and deduce 4 training zones for you. These zones are either to promote fat burning or an increase in fitness level. You also get a cardio program with distinct daily workouts to focus on these zones.

My test was this afternoon and I had no food or any calories for 4 hours before the test including no coffee, alcohol or exercise.

So the 2 tests were intense and uncomfortable. The first one was measuring BMR and I just laid there breathing through a tube with my nose plugged for 25 minutes. I actually fell asleep.

The second test I was hooked up to a heart rate monitor (HRM) and had a breathing mask on. I walked on a treadmill for 12 minutes. Every minute he would up the speed and incline until it got crazy!!!

The first test showed that my BMR is 40 percent lower than average. Almost 900 calories only. Shocker!!! I always went by the scooby calculator and my Fitbit which is based on the average female who is my height and weight - 1350 calories. This test means my Fitbit is 400-500 calories inflated and I've probably been eating at maintenance all this time. ???

My fitness test came back as 'excellent' and almost in the 'superior' range which is very validating considering how I've consistently worked out (30 Day Shred/ChaLEAN Extreme/running) almost every day since January. It also showed how I burn calories - 40 percent from fat, 60 percent from carbs. He said this needs to be reversed.

So we talked about macros and he was impressed with all that I know and do. He was truly stumped why my BMR is so low. He said with everything I've been doing, and everything I know, it shouldn't be that low. Maybe his test was wrong. I don't know. But it could explain why I'm stuck if I've really been eating at maintenance all this time right!??? I've been eating 1600-1800 calories a day which I thought was a 15% deficit from what my Fitbit TDEE is telling me. However, if I go back to my spreadsheet, and deduct 400-500 calories off the average weekly TDEE, I've been eating at maintenance or actually slightly higher than maintenance all this time. I have managed to lose 10 pounds since January and a few inches here and there, but obviously very, very slowly. He suggested I continue to work on upping my protein and ensure I eat protein immediately following a workout and more protein with breakfast. He also suggested increasing fat a little bit too.

Any thoughts on this test would be most appreciated. The research I've done on it shows it is WAY more accurate than the online calculators.