Getting Leaner with Metabolic Flexibility: A Tip from Mike T Nelson

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Note from Paul:  I wanted to talk a bit about this tip because it could be (and often is) misinterpreted.  Certainly, Mike isn’t saying you shouldn’t eat fibrous carbs throughout the day.  So there is that.  The carbs you want “around your workouts” are starchy carbs like sweet potatoes, rice or Vitargo.  Lastly, this doesn’t need to be the time you load ALL of your carbs; I like to have some carbs before bed as well.  When you add up the starchy carbs, incidental carbs from other foods, and dessert before bed, that provides a great balance that sets you up well for your workouts.

While it seems hard to believe, a vast majority of your calories are spent just running your body.  The geeky term is “resting metabolic rate” (RMR).  RMR is the amount of calories it takes to fuel your body while you lay there and do nothing but breathe.

Since your RMR contributes the largest portion of your daily “caloric drain” it makes sense to fuel most of it with your own body fat!

Note – If you are interested in an estimate of how many calories you need, make sure to check out the Eat To Perform TDEE calculator.

The downside is that if you chose to use ONLY fat, your ability to perform high intensity exercise would suck.  Not good.

Therefore, you still want to be able to up-shift and use carbs to fuel your exercise sessions.

As soon as you are done, shift back to using fat again.

Metabolic flexibility (Met Flex) is all about shifting from one fuel source to the next and back.


  • The simplest way to describe Met Flex is that it’s a strategy built around shifting your RMR to burn mostly body fat as well as dietary fat.  You still allow your body to up-shift to a carbohydrate metabolism for performance.
  • Improved performance translates into more muscle; more muscle translates into an increased RMR, and an increased RMR means less body fat.  Boom!  You get the best of both worlds without all the hassle.
  • You can learn more about Met Flex by joining the Science Lab…

Mike T Nelson, MSME, CSCS, PhD