Does % of Fat vs. Carbs Burned in an RMR Test Have Performance Indications?

[Sara]

I got an RMR test done at the lab (just before an AeT test). At rest, I was burning 99.1% carbs vs. 0.09% fat. (Yikes.) Luckily, when doing the AeT test, the fat vs. carb burning ratio worked as expected as pace/HR increased. The person administering the test said he only saw this type of RMR ratio one other time. Has anyone else come across this situation or otherwise knows if it has performance or other metabolic implications? Is the % of carbs vs. fat burned at rest trainable at all / does it matter to try to train this?

[Scott Johnston]

Sara:

I’ve never seen this occur before.  You didn’t just eat a high-glycemic sugary snack like a candy bar before the test, did you? 🤦‍♂️ I thought not but figured I might ask because if you had very high blood glucose levels, metabolism in all your cells will be disposed to shift to using that glucose for fuel because glycolytic metabolism, even “aerobic glycolysis,”  uses less oxygen than the breakdown of fats for energy.

From what you say, when you started exercising, your fat/carbs ratio improved and began to look more normal.   That’s good news.  But if I were you, I would monitor your RMR or even blood glucose levels.  I have no affiliation with this company, but I do know some athletes that use this device for monitoring RMR,  It s not cheap, but probably cheaper than a few trips to the lab.

I hope this helps.

Scott

 

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