Why is metabolic flexibility so important?

Caroline Kavanagh | Feb 8, 2018

Sir Philip Randle of Oxford University coined the term “metabolic flexibility” in 1963, when he discovered that vascular tissue could switch back and forth between lipid and carbohydrate metabolism. In other words, your body can run off either higher percentages of carbohydrates or fat.

Why is this important?

From a general health perspective, switching between fuel sources keeps overall weight constant versus the dramatic ups and downs on the scale. For example, If you’re metabolically flexible, when you eat a high-fat meal, the body is able to easily burn the fat rather than storing it and causing weight gain. In the reverse, when you eat a high carbohydrate meal, your body can burn the glucose rather than it staying in your bloodstream and increasing your blood glucose level. Metabolic flexibility means you can quickly switch to burning the macronutrient source that’s available.

For those who are athletes and looking to perform at high levels, utilizing fat and carbohydrate fuel sources with ease is key, especially as fatigue increases. If an athlete is metabolically inefficient at utilizing different sources of fuel this can result in prematurely “hitting the wall” during a race, or a reduction in training performance.

In metabolically healthy people, muscle is metabolically very flexible. During fasting or long duration exercise, fats are preferentially used for fuels. During intense, short duration, burst training, sugars are used to generate cellular energy. In contrast, the fat-burning furnaces—muscle tissue—of overweight and insulin-resistant people have a hard time burning lipids, and preferentially burn sugar (glucose oxidation).

How do you increase metabolic flexibility?

Through Metabolic Efficiency Training we train the body to be more efficient at utilizing our bodies fuel sources. The body switches from using carbohydrates as fuel, to using fat as fuel. This combination then goes back and forth depending on energy needs. If you participate in any kind of endurance exercise or events, you can go longer without “hitting the wall” if your body can easily tap into stored fat as a fuel. By using fat as the primary fuel source during a sustained period of exercise, glycogen stores are preserved and therefore you don’t fatigue as quickly. Performance is improved and this applies to any type of moderate-intensity exercise.

How do you know if you’re metabolically flexible?

You can measure metabolic flexibility in a lab setting. The Metabolic Efficiency Assessment test monitors how much oxygen you inhale versus how much carbon dioxide you exhale. This information is calculated through a respiratory exchange ratio (RER). RER is the ratio of how much carbohydrates versus fat you’re burning.

Based on your unique test results daily nutrition recommendations are made and the process in becoming more metabolically flexible begins! Through daily nutrition we can train the body to be more efficient at utilizing all available fuel sources and become better fat burners.

Whether your goal is to lose weight or increase performance, metabolic flexibility is key.

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