How Do You Measure Metabolic Flexibility?

How do I measure metabolic flexibility? There are a few different ways that you can go about measuring how metabolically flexible you are. There are some objective metrics, which are going to be more like nerding out on the sciency stuff. And then there's more subjective metrics, which are based off of kind of how you're feeling throughout the day. So let's go through both of those areas.

How Do You Measure Metabolic Flexibility?

Let's touch on the objective ways to measure metabolic flexibility first. 

1. Monitor your blood sugar throughout the day.

This is really getting a little bit on the nerdy side of things. So if you are someone like me, who likes to nerd out on the data, measuring your blood sugar can be a really great way to see how your body is responding throughout the day. Simply use either a continuous glucose monitor or do a finger prick to measure blood sugar at different times throughout the day.

In terms of measuring it, when you wake up in the morning, a good sign of metabolic flexibility and kind of overall blood sugar health would be having a fasting blood glucose of around 90 or below. That's generally a good place to be in, in terms of fasting blood glucose. However, when we're talking about your response throughout the day, that would be looking at your response to meals. When you eat a meal, how do you feel after that meal—you can actually track your blood sugar throughout the day to see how it's responding to a meal that you ate. 

After you eat a meal, it typically will go up and then it should come back down to baseline. If it goes up really high and then kind of crashes down, that's not such a great sign. Measuring your blood sugar throughout the day can give you some idea of you know how metabolically flexible you are. So if you're on the blood sugar rollercoaster, that's probably not a great thing. Because your energy is going to be all over the place. And you're just not going to be feeling great.

2. Measuring your ketone levels. 

Again, this is another way to kind of nerd out on the data. If you have a ketone monitor, so like a blood monitor, same as I mentioned, with the measuring your blood glucose, there are monitors that you can measure your blood ketone levels. You can also do it in your breath and urine, but the blood measurement is going to be typically the gold standard in measuring ketone levels.

If your goal is to get into a state of ketosis for you, measuring how long it takes you to get back into ketosis after you eat a carbohydrate-rich meal—the faster you can get back into ketosis after eating a carbohydrate-rich meal, the more metabolically flexible you are. That's because your body is able to efficiently shift back into that state. So that would be a metric of measuring your blood ketone levels to see how long it takes you to get back into ketosis after you've eaten a carb-rich meal.

3. Measure your ability to train in different energy systems. 

We have different energy systems in our body—we have mainly the anaerobic and aerobic systems, and those sound like fancy words. But aerobic just means low-intensity exercise—cycling on a spin bike or just walking. You're using your aerobic system—you're using oxygen to fuel that.

Anaerobic would be more so using a little bit of higher intensity. So you're doing sprints, lifting, or high-intensity rowing. The thing to realize here is that it's not that you are in each system at one time, your body actually goes back and forth between those systems as you're working out. It's really more so like a dimmer switch than just a light switch that goes on and off. So that's just something to be aware of and your ability to kind of go back and forth between those energy systems and workout with ease is a good sign of metabolic flexibility.

Tracking your performance over time, and using that as an objective metric, like, are you getting better at working in these different energy systems and getting more efficient at them—that would be a good sign of overall metabolic flexibility from an exercise or prefer performance standpoint.

Subjective Metrics for Metabolic Flexibility

In terms of the subjective metrics of how to measure your metabolic flexibility, these are going to be more so how you're feeling throughout the day. So when you wake up in the morning, how do you feel? How do you feel during your exercise sessions? How do you feel after you eat certain meals? These are gonna be more of the subjective feelings, right—so I did a whole video on this, but we'll dive into a few of them today as well.

1. Your Ease of Fasting

The first subjective metric would be your ease of fasting. When you wake up in the morning, do you have to eat right away, or can you go, you know, an hour or two hours or five hours without eating? That is going to be a sign of, you know, good metabolic flexibility and good blood sugar regulation. Ease of fasting is a really good sign that you're metabolically flexible. And so when you're going throughout your day, like if you're able to skip meals, or if you're able to have a meal and then not eat for a long period of time, that's going to be a great sign that you are metabolically flexible. That's because you're able to tap into your body and use the energy storage you have available.

2. Energy Levels Throughout the Day

The next subject of metric of measuring your metabolic flexibility would just be looking at your energy levels throughout the day. How are you feeling as you go about the day when you wake up in the morning? Do you have to grab a cup of coffee right away? Or can you go a little bit without caffeine?

As you go throughout your day, are you having good stable energy when working? Do you have good mental focus and clarity? Those are all signs that you have good energy—you're feeling good throughout the day. And that can be really a sign that you're metabolically flexible.

Obviously, sleep is a big component of that. But, you know, we want to make sure that we're going throughout our day with good energy levels. And that is a good way to kind of measure how metabolically flexible you are. If you have good energy, good focus and good mental clarity throughout the entire day.

3. Ease of Eating Carbs

Another subjective sign from measuring your metabolic flexibility would be your ease of eating carbohydrates. When you eat a carbohydrate-rich meal, how do you feel afterward? Do you feel like your energy crashes? Do you feel like you need to go take a nap? Do you feel bloated and you have some digestive issues? Those would all be signs that you're not utilizing those carbs efficiently.

When you eat a carbohydrate-rich meal and you feel good afterward, that is a good sign that you're metabolically flexible. And that just kind of goes off of that subjective feeling. So your body is able to utilize those carbs efficiently. And that would be a great sign that you're metabolically flexible.

4. Exercise Performance

Another way to subjectively measure your metabolic flexibility would be kind of looking at your exercise performance. How do you feel when you're exercising? Are you able to exercise in varying intensities?

Your ability to exercise in those different or varying intensities is a good indicator of your metabolic flexibility. So your ease of being able to progress within those different energy systems. And what I mean by that is just your ability to work out in that low, moderate and high intensity energy systems. That would be a good way to measure how metabolically flexible you are, and your progression through those as you go.

5. Emotional Feelings

Another subjective way to measure your metabolic flexibility would be more on the psychological or emotional side of things.

How easy is it for you to eat carbohydrates? How easy is it for you to eat fat? So do you fear eating carbohydrate-rich foods or do you fear eating high-fat foods? If you are able to say I don't fear eating any of those and I don't have any really emotional connection to those, that's a good sign that from an emotional standpoint, you are metabolically flexible.

That's because you're able to eat those foods and realize that they're just fuel. There's no morality behind food groups. They're just food and fuel—they have macronutrients. And so if you can kind of do that with ease and you realize that, you know, there's no emotional connection to those food groups, then that is a sign that you're emotionally metabolically flexible.

Those would be the most common objective and subjective ways to measure metabolic flexibility. They aren't the only ways but those are the ones that I've seen to be the most reliable and telling you how metabolically flexible you are.

Want to learn more about metabolic flexibility? Browse the blog and podcast to learn more—we have plenty of content on the topic!