Metabolic fitness is a fancy term for the body’s ability to conserve muscle glycogen and function on “alternative fuel”

Engaging in endurance sports like triathlons, duathlons, and marathons, it’s easy to focus on physical fitness alone. For a lot of people, it’s all about getting faster and stronger. However, come race day, the training they do seems to be all in vain.

The long rides, epic runs, and hard swims appear to work, maybe for 75 percent of the race; then, all of a sudden, performance starts to drop. Some attribute it to a lack of training, hence they do more, push harder, and rest less frequently, to no avail.

So what is the problem? Metabolic fitness might be lagging.

Metabolic fitness is a fancy term for the body’s ability to conserve muscle glycogen and function on “alternative fuel.” I use the term alternative with a grain of salt as it really should be the primary fuel to begin with. However, because of our lifestyle, diet, and how our untrained bodies function, it becomes the second option.

Usually, for short distances (up to sprint or maybe even Olympic), being too carbohydrate dependent won’t do too much harm. That’s because the fuel tank can still handle the mileage. Go beyond that and it starts to become an issue

Without being too technical or geeky, our body can either burn carbohydrates or fat to produce energy. Carbohydrates are like liters of gasoline. They burn fast, are easy to replenish, pack a huge punch, but are very limited in supply.

On the other hand, fats are like renewable energy such as solar power. They last long and have a ton of supply but aren’t as explosive or convenient. This analogy is great as it shows us that the type of fuel we choose will greatly influence our performance, specifically, our endurance.

Usually, for short distances (up to sprint or maybe even Olympic), being too carbohydrate dependent won’t do too much harm. That’s because the fuel tank can still handle the mileage. Go beyond that and it starts to become an issue. Now it begs the question “What do we do?” It’s all about improving the body’s ability to utilize fat.

Let me first clarify that carbs are still important. Physiologically, we need carbs to burn fat via the Krebs Cycle (our aerobic engine). In extreme cases, such as complete carbohydrate depletion, our body shifts to ketosis. Which, in my honest opinion as a professional, isn’t necessary to pursue. You can, but you’ll save yourself a lot of time and effort if you just improve fat burning with carb utilization. With that out of the way, let’s talk about how you can improve metabolic fitness:

Do lots of volume at Zones 1 to 2

If you’re not familiar with zone training, there are lots of resources to explain what they mean. In a nutshell, Zones 1 and 2 are aerobic (easier) intensities that maximize fat metabolism. Also known as the “fat burning zones,” staying here allows you to achieve a few things. First, as mentioned, it teaches your body to burn fat and conserve glycogen (muscle carbohydrate stores). Second, it allows you to do more volume, which in turn goes back to being able to do the previous point even more.

As a general rule of thumb, unless you’re doing an Ironman, try and build towards a long workout of 125 to 150 percent of the race distance. It seems overkill for some but if you really want to do well, this is an “easy” way to do it.

Hydrate with water more

Marketing has told us that if you engage in sports, you need these carbohydrate-rich “sports drinks” to function properly. While technically true, we tend to overdo it. We store carbohydrates in our bodies and only need to top up if the duration exceeds 60 to 90 minutes (usually). There are some exceptions to the rule; for example, if the intensity is very high or the body’s ability to utilize fat is extremely low. In the case of the latter, gradually minimizing carbohydrate supplementation is necessary.

For your Zone 1 to 2 workouts, take note of the point where you feel fatigued and in need of that carb boost. The goal is to progressively delay your body’s fueling timeline

To be effective, weaning the body from carbohydrates needs to be done gradually. For your Zone 1 to 2 workouts, take note of the point where you feel fatigued and in need of that carb boost. The goal is to progressively delay your body’s fueling timeline. Once you reach 90 minutes, there is little benefit to push beyond that.

Control your carbs

Related to the previous point, carbohydrate control also goes beyond training. Your diet outside your workouts compromises around 80 to 90 percent of the bulk. It makes sense to focus on it as well as it makes a larger impact on your metabolic fitness.

The bad news is that the typical Filipino diet is too carbohydrate-rich. This is an understatement as our usual food intake sometimes goes up to 80 percent carbs. My advice is to limit the rice, bread, and desserts. Instead, take more quality protein and vegetables. Doing this, without any calorie counting, works wonders already. If you want to go into more detail, I suggest doing a metabolic test like what I do in the lab. This will take into account your individual burn rate (metabolism) and fuel preference.

To improve metabolic fitness, fast

Yes everyone wants to go fast, but nobody really wants to fast. Now let me point out that this isn’t absolutely necessary but I’ve found that if done right, it helps a lot.

Just make sure that when you do intermittent fasting, you still eat properly and not pig out on donuts and cake during the feed periods

Fasting can be done in two main ways. The first one is to do fasted-state training; this means doing your workout immediately after getting out of bed. No calories taken beforehand, just water (a lot of it). This recommendation applies if your workout isn’t too intense or long. In other cases, you need to take some calories in before you sweat it out.

The second fasting method is to do intermittent fasting. IF, as some people call it, gives you feed periods and fast periods, usually six hours in length. Again, this isn’t necessary but for those struggling with metabolic fitness, it can help a lot. Just make sure that when you do this method, you still eat properly and not pig out on donuts and cake during the feed periods.

Supplement with L-Carnitine

Don’t be disappointed, this isn’t an advertorial. There is really a lot of research backing up the efficacy of L-Carnitine in terms of metabolic fitness.

Physiologically, L-Carnitine is an amino acid that allows fat to be taken up by the cell and converted into energy. For people who don’t consume a lot of meat (most probably people like us), L-Carnitine is usually in short supply.

Supplementation gives your body the best chance of improving metabolic health severalfold. In my lab, I’m able to see athletes lessen their carbohydrate dependency by 25 to 40 percent within a couple of months just by supplementing with L-Carnitine.

The only other problem with this amino acid is that the traditional way of taking it is inconvenient. L-Carnitine capsules are usually big, bulky, and easily break apart because of the humidity in the Philippines. I switched to liquid capsule-based ones such as LeGarde since it delivers the supplement to the body more effectively.

Of course there are other ways such as through syrups and drinks, so it’s all about choosing what works. Just remember to take your L-Carnitine after meals or snacks as it works best with an insulin spike.

Just remember that sports performance isn’t all about training. There are also physical, emotional, mental, and even metabolic factors we must consider. The best way to cover all these things is to reach out to a well-versed professional who can help you. At the end of the day, taking care of these will not only help you perform better, it will also improve your quality of life.