Metabolic Flexibility: Switch from a Sugar Burner to a Fat Burner
When I was just learning about blood sugar, I thought what many of us think: since sugar and starches cause a rise in blood sugar I’ll just never eat them! Queue a serious low carb stint, totally unsustainable, followed by a fear of carbohydrates. I know I’m not alone, with the Atkins, Keto, and even Carnivore crazes, we’ve all drunk the crazy (low-carb) juice and are suffering from a deficiency in … information.
Here’s the truth, and it feels really, really good to know: you can have your carbs and eat them too. In moderation, of course. The goal is to train your body to be metabolically flexible.
What is metabolic flexibility?
Metabolic flexibility is a fancy term that simply means you are able to function well no matter which fuel source you have (sugar or fat) or exercise intended (slow aerobic or fast anaerobic). Basically, you should be able to eat zero carbohydrates today (for some reason) and not fall on your face with carb flu, or eat some excess (healthy) carbohydrates without a huge blood sugar spike. You should be able to walk long distances or suddenly sprint or climb (or do some HIIT exercises) without feeling like you’re dying.
To give you an example of metabolic inflexibility, I’ll tell you about me, circa 2010. I was addicted to snacking, carbs, coffee, sweets, and wine. I would have a blood sugar drop and get the shakes if I didn’t bring a snack to the beach and eat immediately after I surfed or ran. If someone had told me to eat low-carb for a day, my body would have gotten sick and miserable. And my body had zero idea how to tap into fat as fuel, I was running on sugar with no aerobic base leading me to injury after injury (I’ll explain what this means in a sec).
As you can see, this body was wound up, stressed, and inflexible! The cool thing now is that I, with the same body, have mastered metabolic flexibility. I can burn fat for fuel easily, conquer a day without carbs (if I had to, not saying I do this regularly), I never get blood sugar drop shakes, no longer snack, and have forsaken alcohol. I am stronger, less injury prone, and have stable, consistent energy.
How did I get here? There’s a formula! You can follow the formula too. First, let’s learn the basics
Humans have white and dark meat too
Learning the difference between aerobic and aerobic exercise is the best thing you can do for your body to become a stronger, healthier person. And it’s probably not what you think. It has to do with the question of aerobic versus anaerobic. I’ll explain…through a chicken.
Chickens have both dark meat and white meat. Dark meat is more delicious since it stores the fat of the bird (the energy, if you may), and it’s also much less chewy, stringy, and “brittle” than white meat, which stores little fat.
Why the difference? It’s all in the muscle fibers, and the fuel they require to properly behave!
Dark meat is actually red muscle fiber. It’s known as “aerobic” because it slowly burns fat for energy, a complex process that requires oxygen (hence “aerobic”: needing oxygen). They’re also known as slow-twitch muscles because of their relatively slow contraction. Slow-twitch muscles give your body a strong frame. These guys are the ones continuously holding you up in your joints, feet, and structure. They are not easily fatigued and, in fact, can go for days without exhausting. Again, think of the chicken: their dark meat is in their legs so they can walk around all day without tiring.
White muscle fibers are different in every way! These are “anaerobic” because these fibers quickly burn sugar for fuel (think, explosion), a process that doesn’t need oxygen. With this energy explosion, they can move fast—3x as fast as their red muscle counterpart—which allows you to sprint fast, fight strong, or do any fight-or-flight activity … even stress. If you’re pushing yourself to your limit (even if you’re not going fast, per se), you’ll be tapping into this muscle fiber. They are easily fatigued and can really only push 30 seconds to 1 minute. Again, think of a chicken: their white meat is in their breast and wings since they only fly when they feel in danger. And boy, can wild chickens fly!! (We have more chickens than people on the island of Kaua`i, FYI, fun fact).
Back to people, we also have the same two types of muscle fiber! But our own muscle fibers are woven together throughout each of our muscles, so both red and white are woven into a tapestry throughout our bodies rather than in sections like that chicken. Yup, your legs aren’t just red, they’re red and white, slow-twitch and fast-twitch, aerobic and anaerobic. They can burn sugar or fat, sprint for a little bit or walk for a long while. And … we can over strengthen one system at the expense of the other, leaving us metabolically inflexible.
The problem arises in the question: which system do you predominantly use?
Are you a fat burner or a sugar burner?
Can you go for a day without sugars (even healthy ones) without falling over “exhausted”? Can you run or do exercise while maintaining a low heart rate, or are you out of breath quickly? Do you crave carbohydrates all the time, especially in times of stress or after exercise? Does your posture suffer, no matter how much you try to correct it, or do you get injured often? Then you, my friend, are probably a sugar burner.
Being a sugar burner is really an informal way of saying your anaerobic (white meat) system is overdeveloped, while your aerobic (red meat, fat-burning system) is underdeveloped. This means your fast-twitch anaerobic muscles are always at the ready, primed for fight-or-flight, be it at work or while exercising, and definitely make their plea for sugar in the kitchen. They’re the ones that need the fuel, after all.
As for your slow-twitch muscles—the ones responsible for strong posture, less injury, more stamina, and run-on fat—, they may be totally on vacation.
It’s not that white muscle (anaerobic) behavior is evil, it’s that many of us have come to rely on it as our predominant system used and the only one we feed. We are constantly revving it up by doing activities like high-intensity workouts, by pushing ourselves too fast or too far, by trying to outcompete others, or even by the simple stresses of daily life. Yes, your body will react the same way to stress as it does by sprinting 100 yards, by tapping into the “fight or flight” response of your white muscle fibers! That means if you’re running from a lion or stressing over your job, the same system is going to be used.
This leaves your body constantly relying on sugar to fuel you without remembering how to use fat as fuel, or red muscle fiber for stamina, strength, posture, etc. It may be why you went lower carb but still have blood sugar drops, chronic stress, or crave sweets with the might of the Cookie Monster. This leaves us with…
Aerobic Deficiency Syndrome (ADS): Uh oh, I bet a lot of us with endometriosis have this
You can be a couch potato, a moderate athlete, or highly trained athlete and still have Aerobic Deficiency Syndrome (ADS). It’s not choosy. ADS simply happens when the aerobic system is not well developed, and the body uses the anaerobic system for nearly everything: energy, movement, and posture.
The cool thing is you can change this! There is totally a method to develop your anaerobic system and lessen your reliance on your anaerobic, sugar-burning system. It involves 2 very specific parts:
1) Your food: your blood sugar MUST be balanced in order to starve your sugar-burning engines and prime your fat-burning ones. I have a blog here on it.
2) Your exercise: you must focus exclusively on building your aerobic base in order to retrain your body to use red muscle fiber. The rest of this blog post will be dedicated to this!
How to build your Aerobic Base For Endometriosis
Don’t worry, I’m not going to suggest any intense workout here! Quite the contrary. In order to build an aerobic base, you need to do low-intensity activities that tap into your slow, fat-burning system. It doesn’t matter the type of exercise as long as you stay in your aerobic threshold without going into your white-muscle anaerobic mode.
If you’re like “Katie, how the heck do I know if I go anaerobic???!” I here have the answer for you.
Let Your Heart Rate Be Your Guide
If you want to know when you’re switching from your fantastic aerobic system usage to your crazy-stressed-fast-twitch-white-muscle system, all you need to do is track your heart rate (with this formula) and don’t let your heart rate go over this number:
Take your age and subtract it from 180.
Now modify based on the following
If you have or are recovering from a major illness or are on any regular medication, subtract an additional 10.
If you are injured, have regressed in training or competition, get more than two colds or bouts of flu per year, have allergies or asthma, or if you have been inconsistent or are just getting back into training, subtract an additional 5.
If you have been training consistently (at least four times weekly) for up to two years without any of the problems in (a) and (b), keep the number (180–age) the same.
If you have been training for more than two years without any of the problems in (a) and (b), and have made progress in competition without injury, add 5.
For example, I’m 31 and in good health now, so my number is 149 (180-31, no modifications). When I started last year at age 30, I subtracted an extra 10 for endo, allergies, poor immune function, and chronic injuries. So it used to be 180-30-10 = 140.
Once you find this magic number you have to monitor yourself while exercising to make sure you don't go above it.
How to Track Your Heart Rate?
The best way to do that is to get a quality heart rate monitor. DO NOT USE the Fitbit watches, they have been shown time and time again to be inaccurate when reading your heartrate (plus I heard they can make people become obsessive-compulsive... talk about extra stress!).
The best for exercise is a traditional loop-around-the-chest HR monitor that doesn’t get moved or jostled. You can buy either the watch kind (more expensive) or ones that sync with your iPhone and an app. (I this one and it works great).
If you’re not keen on spending the money right now, you may be able to generally guess this rate by…nose breathing! This is a really cool hack. Yeah, no fancy heart rate monitor is needed, just workout while nasal breathing, and if you get to the point you feel like you need to breathe through your mouth, slow way down until you’re happily nasal breathing again.
Depending on your body it may not be a problem to stay below this heart rate, or you might feel so slow that you want to punch something. You may honestly find if you do more than a fast walk your HR skyrockets. No matter where you are, know that as you build your aerobic base you’ll be able to go further and faster without raising your HR to its limit.
Example: When I started jogging at my aerobic heart rate it felt nice and mellow, but I couldn’t run up hills without walking because my HR would soar. So I walked up hills to keep my HR low. As the weeks progressed, I noticed that even though my HR was the same (low) I was running miles faster and could slowly jog the hills without stopping. After a few months, I was cruising at a pretty fast pace for me without getting near my HR limit. I was watching my aerobic base strengthen without my usual onslaught of injuries. So if you're either dying at the slow pace or craving your fast pace again, give it time. You'll be up to speed in no time.
How Aerobic Base Training Increases the Right Kind of Circulation
Great circulation allows blood to saturate your muscle surface evenly and thoroughly
Have you seen a river basin before? They’re beautiful. And they look just like your circulatory system does when it’s well developed. Your arteries are like the huge river, and all the capillaries are the rivulets that fork off, bringing water and life without blowing out the natural landscape. If you imagine your circulatory is the same way, you want your arteries to slowly bring blood to your muscles, and then have them pool into the capillaries, feeding all your muscle fibers and bringing oxygen while taking away debris and toxins. That’s what your circulation does! So if you speed on up to your max HR you’re creating more of "garden hose at full blast" style circulation, forcing blood into your arteries like an explosion that doesn’t allow it to slow down enough to feed into the little capillaries and nourish the rest of your body.
Same for the cool down. You want to allow your blood ample time to slowly pack up and leave your muscles. Not only will this make your circulation function better, you’ll also be less sore, have more energy, and have increased aerobic performance.
Even if you only have 30 minutes, it’s better to warm up to your HR then immediately start the cool down rather than rush your body. Especially as you just start working to strengthen your aerobic base.
Lastly, if you're plodding along no where near your aerobic threshold do not force yourself to get there! Listen to your body and only do what you can. You're getting all the aerobic benefits by staying below that number, even if it's way below.
The time it takes to establish a solid aerobic base will depend on where you’re at now, but be open to giving it 3-6 months. That’s 3-6 months without going over your aerobic threshold, so be patient with yourself if you’re either starting from scratch, or used to being the fastest in the pack.
Disclaimer:
I am not a dietitian, doctor, or medical professional, this site is solely for guidance and information to give people more information to make an informed decision about their own bodies best treatment plan. It’s a source of information that helped me put my own endometriosis in remission, and information I wanted to share for anyone else it might help on their journey.