Yet another meal-timing study ... to the highest degree and keep the ability to SWITCH ... Minnesota, an MS in Mechanica
Research Digest Exclusive Sneak Peek
Issue 8
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June 2015
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Table of Contents A hole in the bucket: gliadin and intestinal permeability Understanding what happens at the intestinal barrier is key for understanding reactions to wheat
Metabolic flexibility: The argument to use both carbs and fats By Mike T. Nelson, PhD
Blast from the past: a paleo solution for type-2 diabetes The evidence continues to build for ancestrally-influenced diets
Vitamin (K)ardiovascular health? Results are in from the first long-term trial of vitamin K2 for cardiovascular health
I get by with a little help from my friends: probiotics and depression Mix a few beneficial probiotic strains, take daily, lower your chances of depression?
Big breakfast or big dinner? Yet another meal-timing study Eating the exact same meals, but in a different order could help stabilize blood sugar
Green tea extract may not be an equal opportunity fat loss supplement Does this common fat loss supplement actually work? And how might it produce its effects?
Ask the Researcher - Eric Helms, PhD(c) A go-to source for natural contest prep, Eric gives us some sage advice on macros
INTERVIEW:Shawn Wells, MPH, RD Part two of our interview delves into supplement quality, leucine, and more
Metabolic flexibility: The argument to use both carbs and fats By Mike T. Nelson, PhD
There is currently a debate about which fuel source is
olism. But metabolic flexibility, which is the area I
the best. Low carb proponents advocate the use of fat as
studied for my PhD research, is actually looking at both
your main fuel source.
metabolisms and how your body switches back and forth between the two.
On the other end of the spectrum, people expose the power of carbs to get you through a hard weight train-
On a day when your activity level is lower and you are
ing session.
not moving around much, you would generally want to be able to use fat as the primary fuel source. Why?
Who is right?
Because it’s going to help body composition; there’s no need to use carbohydrates for low level activity.
In my biased view, BOTH of them are right. Now, if you go to the gym and you start lifting weights You want to increase the use of BOTH fats and carbs
(which I highly recommend, especially for fat loss and
to the highest degree and keep the ability to SWITCH
performance, of course), you want to transition to be
back and forth as needed. The fancy term for this is
able to use carbohydrates because that’s going to give
“metabolic flexibility”, which was first coined in research
you a much higher performance. You will be able to do
by Kelley and Mandarino in 2000. When you lose this
more; you’ll be able to lift more in the gym.
(metabolic inflexibility), your risk for diseases such as type 2 diabetes increases.
Research has shown that those who are on a very low carb diet for prolonged periods of time demonstrate a
Metabolic flexibility allows you to use fat at a higher
reduced ability to fully use them during exercise.
rate (better fat loss) while still maintaining the ability to use carbs (better performance). BOTH fats and carbs
Metabolic flexibility allows you to get the best of both
are useful, and there is no inherent need to eliminate
worlds by using carbohydrates for fuel during exercise
either one from your current plan. And there is no rea-
and fats for fuel the rest of your day.
son to waste your precious time debating this on the ol’ interwebz.
But what about the ketogenic diet?
Metabolic flexibility is, in essence, how your body tran-
I get emails saying that if the goal is to ramp up the use
sitions between fats and carbohydrates. People tend to
of fat, I need to recommend a ketogenic diet.
focus on either fat metabolism or carbohydrate metab-
BOTH fats and carbs are useful, and there is no inherent need to eliminate either one from your current plan.
I think that a keto approach MAY work okay for some
need the ability to “drop the hammer” and power past
ultra endurance athletes, but the catch is even they will
the competition using carbs as a fuel. I have not seen
still have periods where they need power.
data showing that ketones as a fuel source can match carbs for power output.
A ketogenic diet is one that is moderate to low in protein and super high (sometimes up to 80%) fat, with
In summary, you want to fuel your training to the
very low carbs (commonly 30-50 grams a day).
highest degree a vast majority of the time, and this requires carbohydrates to produce high power outputs
To put it in perspective, if you ate one whole bagel per
and speed. You should also have periods of time where
day, you would be over your allotment of carbs on a
carbs are lower to allow your insulin levels to drop and
keto diet.
push your body to use more fat (increased fatty acid oxidation). Fatty acid oxidation rates during low inten-
Let me tell you a short story about the power of carbs
sity exercise are highly variable. This is typically done
(which are very limited on a keto diet).
when you are not doing a heavy anaerobic session.
I was a crew/ support/nutrition person for the RAAM
Metabolic flexibility explains how our bodies use both
(Race Across America) several years ago. Despite it
fats and carbohydrates for fuel. Generally, we want to be
being a long race (7 days to pedal a bike from San
using fats for fuel in our daily lives and carbohydrates
Diego CA to Atlantic City on a 4 person team – yes,
for fuel during training sessions. So, to take advantage
you read that right – a PEDAL bike not a motorcycle)
of the wonder of metabolic flexibility, increase carbo-
the average power output was quite high.
hydrate intake before and after a training session, and decrease carbohydrate intake when you’re just sitting
Add in wind and the fact that there’s no drafting, so you
around reading this article. Put down that bagel!
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Dr. Mike T. Nelson CSCS has spent 18 years of his life learning how the human body works, specifically focusing on how to properly condition it to burn fat and become stronger, more flexible, and healthier. He’s has a PhD in Exercise Physiology from the University of Minnesota, an MS in Mechanical Engineering (biomechanics) from Michigan Tech and a BA in Natural Science. He’s an adjunct professor and a member of the American College of Sports Medicine, The International Society of Sports Nutrition and the American Society for Nutrition. He’s even been called in to share his techniques with top military agencies. The techniques he’s developed, and the results Mike gets for his clients have been featured in international magazines, in scientific publications, and on websites across the globe. Go to his site at miketnelson.com.
