Are you “Metabolically efficient?” by Debbie Potts
How efficient is your body at utilizing stores of carbohydrate and fat at various training heart rates, duration and at rest?
Learn how to become a Fat Burning Machine! Learn how to burn more fat and preserve your carbohydrates stores.
Learn how to train and what to eat makes a difference in our ability to use stored fat for fuel.
• Do you train and compete in endurance events two hours or longer?
• Do you eat a “high carb meal” before your workout?
• Do you eat 200-300 calories per hour of sports drinks, gels and bars when you train or race?
• Do you ever have GI distress during a race?
• Are you trying to get faster?
• Are you trying to lose fat weight to get leaner?
I have been training for endurance events since I was 25 years old, including long distance cycling events, Ironman distance triathlons, marathons to 50k trail races. For the last fifteen plus years I have wondered why I keep eating high carb “healthy” meal before a workout, then eat gels, bars and drink mixes to keep me “fueled” during my work. I have raced with various drink mixes and still have a habit of “eliminating excess liquid” from my bloated belly while I am racing (typically on the bike).
I have been in the fitness industry for twenty plus years as a trainer, coach and fitness program coordinator and manager….eating high carb “athlete” food plan never made sense to me. For years I have trained by heart rate, built up my aerobic engine and improved my ability to burn fat for fuel. Now I have finally figured out how to not only train right, but eat right, in order to be metabolically efficient.
As a coach and trainer, I have trained clients for years on “how to train by heart rate” and conducted metabolic assessments with New Leaf Metabolic Assessments on the treadmill and/or bikes. The information from the metabolic assessments is invaluable for any endurance athlete training for an event or anyone just trying to lose fat weight. We can now also figure out how to improve and move your “Metabolic Efficiency Point” through a proper training and nutrition program. We need to figure out which heart rates do we burn the most fat for fuel for endurance training, tempo ranges and speed work, but also what to eat (or not eat) before, during and after workouts.
Definition of Metabolic Efficiency: The body’s ability to utilize fat as the main fuel source while sparing the limited amounts of stored carbohydrates. Which fuel source makes more sense to use for endurance events? 80,000 calories stored fat or 2000 calories of stored carbs?
A metabolic assessment will determine and measure the following information:
• Aerobic Base (AB): the highest heart rate (and range) where you burn the highest % of fat for fuel
• Anaerobic Threshold (AT) : where you are no longer burning fat for fuel; VCO2 is higher than VO2.
• Respiratory Exchange Ratio (RER or RQ value)
• Metabolic Efficiency Point (MEP): where you begin to burn more carbohydrates than fat
• Peak volume of Oxygen (VO2 ml/kg/min)
• Recovery heart rate and fuel source used post AT
Training Zones/RER:
Zone 1: Recovery and Warm-up
Zone 2: Endurance training
Zone 3: Tempo
Zone 4: Threshold
Zone 5: VO2 training intervals
Why should you train below your “MEP” or “AT”?
Once you go near or above your tested anaerobic threshold you are no longer burning fat for fuel and depending on carbohydrates for fuel. If you continue to train or race above your “AT” then you are limited on fuel source (carbohydrates = 1200 calories as stored muscle glycogen) and you will need to consume more calories each hour to resupply your muscle glycogen stores. If you want to tap in to the estimated 80,000 calories of stored energy from fat fuel then you need to stay in your aerobic ranges the ENTIRE time of your workout or at least the majority first half or more.
From the Metabolic Assessment, we can measure your recovery heart rate and fuel uses (RER) after you hit your anaerobic threshold (you are not using fat for fuel anymore). Even if your heart rate drops back to “zone two” aerobic endurance training or “zone one” recovery range, you may still be burning primarily carbohydrates for fuel. We can see this lack of return to burning similar % of fat calories at lower heart rates post anaerobic heart rates in treadmill assessment tests as well as during training workouts.
How many times does someone start a beginning of a bike or run up a small hill without watching their heart rate? Their heart rate soars up above their anaerobic threshold zone and continues the rest of their workout or endurance race using carbohydrates as their main fuel source. Result? Bonking early in training workout or race and then over eating sugar “performance gels or bars” to find energy, then battling stomach/GI issues.
Learn more about what to eat before, during and after a workout on upcoming “FIT FAT FAST” podcasts and blogs on www.fitnessforwardstudio.com.
