Through my current work situation, I am fortunate to have access to a state of the art, gold standard metabolic cart to do Metabolic Efficiency™ assessments on a variety of athletes.
A bonus of having access to this equipment is to test the short- and long-term effects of different dietary and training interventions on myself. It's actually been a while since I've used the cart for my own testing due to various reasons. Most notably is the fact that my nutrition patterns have been fairly consistent and my training this year has been pretty low key (due to the bike accident and residual injuries earlier in the year).
I decided last week it was time to check out my current ‘metabolic status’ to have new baseline. For those who don’t know, Metabolic Efficiency™(M.E.) testing is mainly a nutrition assessment, not a performance-based assessment like VO2peak or lactate threshold/clearance testing. In a nutshell, by doing a M.E. test, I get an accurate indication of how my daily nutrition patterns affect my body’s substrate utilization (fat vs. carbohydrate use and in this case, at different walk/run intensities). There are training-related data points that are gleaned from the testing, but the data are generally not extremely relevant for setting performance-based training zones. [See Bob Seebohar’s book for more background on the concept.]
Here’s a snapshot of my results from the treadmill test:
Note the red line that represents a percentage of calories my body oxidizes (burns) from fat vs. the blue line representing carbohydrate oxidation. If you’re familiar with or immersed in the fat burning rage that is sweeping social media (among other niches) these days, you should immediately be impressed. However, I want to address two questions/concerns:
Question #1: How am I achieving this high rate of fat oxidation?
- I must be following a ketogenic diet, right? Nope.
- I must be using one or more of those exogenous ketone supplements? Nope again.
- I must be a gifted athlete, eh? Ha ha - not even close as you can see looking at my paces.
- Well, then I must have a very strict, disciplined “diet”. Nah to that too.
- I must be doing high volume aerobic work to yield this level of fat oxidation. I wish, but no.
Here’s the thing: I eat to support stable blood sugar levels. I don’t have to count calories or the levels of macronutrients. [Note: I do hold a master of science degree in human nutrition so my knowledge is more than the average Jane.] I don’t spend money on any supplements to get me “in fat burning mode”. I use real food... and I love to eat. Yes, my daily nutrition plan is higher in fat, I control my carbohydrate intake, and protein consumption is not excessive. But, I am not doing an uber LCHF (low carb, high fat) diet nor am I in nutritional ketosis at the current time. I’ve been doing trainer rides and short aerobic-focused runs for the past 3-4 months with some strength work (to rebuild), but no high volume anything.
Here’s the burning question that many individuals have (which I also asked myself): “Do I need to follow a LCHF diet or take ketone supplements to achieve high rates of fat oxidation?" Absolutely not. Do YOU need to do this? Maybe, maybe not. I’m not saying nutritional ketosis is wrong or unhealthy or ridiculous, by any means. There is a growing body of research to show its clinical efficacy. What I am saying though is that if you are lured into the fat burning craze, think for a moment about how you want to do it and whether you want it to be sustainable. Food will always be your most powerful tool to create a positive metabolic environment within your body.
Question #2: Is what you see on the image relevant and useful? Like the be-all-end-all?
For health purposes, more data are emerging to suggest being a better fat burner is more along the lines of our evolutionary origin as humans. Of course, there are studies suggesting the beneficial effects of nutritional ketosis for certain disease states, so one can certainly argue that angle (although this post is not intended to spin arguments).
From other health perspectives, I can tell you I am at a healthy body weight, my blood biomarkers are either in the normal or ideal range, and I have great daily energy and focus. I do it with real food, daily exercise/movement, sleep and good/improving stress management techniques.
Now, from an athletic performance perspective, here’s where I look at the data and I offer you the “So What?”. The paces you see are slow for my abilities and for where I’ve been in the past number of years in my running journey.
So what does it matter if I’m a good fat burner if I can’t run fast, hard, or sustain high intensity efforts? See what I’m saying? This is where my Coach gets to shine and do his job to get my speed and anaerobic side further developed. I get to keep periodizing my nutrition to support my health and performance, monitor and assess, and go from there…all without dropping lots of cash into supplements or doing anything extreme.
I like the sustainable.
By the way, this test was done in the follicular phase of my menstrual cycle for any of you who might be curious.