Keep reading to learn why metabolic flexibility — aka a person’s ability to metabolize various energy sources for fuel — is so important.
Metabolic flexibility simply refers to having an ability to process whatever fuel we consume into energy. Intuitive enough, right?
Think of it this way: most cars run off 91-octane gasoline. Many sports cars run off premium gas. And a good amount of trucks run off diesel. But a select few safari trucks can run off both gasoline and kerosene.
The human body is equally oriented toward survival. For most of human history we simply didn’t have steady access to safe, calorie-dense food. There was a time when we were either hunting down large game, scavenging for berries, or fasting — with not much in-between.
Even just a few hundred years ago, the average person was well-acquainted with occasionally going days or weeks without food.
Suffice to say that the human body evolved with metabolic flexibility in mind. We can run off of sugars (glucose, fructose), fatty acids, ketones, ketone esters, ethanol, and numerous other food sources.We can even convert carbohydrates into fats, and proteins into carbohydrates when other macronutrients aren’t available.
Healthy, metabolically flexible people can switch from burning fat one minute to burning glucose the next. They can also cycle into a ketogenic state when food isn’t around. Their blood sugar also remains under control, sparing them from mood swings and/or out-of-control hunger (the hangry state).
Metabolic flexibility is associated with healthier mitochondria, which in turn are associated with a whole host of health benefits. People who are metabolically flexible live longer and stay healthier than those who are not. [1]
Related: Carbs vs Fats. Glucose vs Ketones.
What’s the opposite of metabolic flexibility?
While you could call it metabolic inflexibility, most researchers instead call it metabolic syndrome.
Metabolic syndrome is marked by an increasingly poor ability to produce the blood-sugar-regulating hormone insulin. It’s also marked by insulin-resistant muscle cells and insulin-sensitive fat cells.
This combo results in poor body composition and difficulty building muscle.
If left unchecked metabolic syndrome invariably leads to type-2 diabetes and other health conditions. Unfortunately, a growing percentage of the population is falling into these categories. The most recent figures estimate that 34% of US adults have metabolic syndrome. That’s just over one in three! [2]
Image source: ResearchGate
Why’d we get here? Because a growing portion of modern humans has lost the metabolic flexibility of their ancestors. Today food is everywhere, so much so that most people rarely find themselves in a situation where they have to go hungry for long. Nor do we have to put in much work to earn a meal.
Making matters worst, the food most people eat also reduces their metabolic flexibility. That’s because these foods are typically high in processed seed oils, processed sugar, and other inflammatory substances.
Metabolic flexibility is associated with a variety of other health benefits, including:
Yes, it sure can! Metabolic flexibility enables your body to burn fat for fuel at rest, resulting in lower fat mass.
In addition to that, the same way of eating that promotes metabolic flexibility also promotes thyroid health and hormonal health. You might find yourself getting leaner as you pursue metabolic flexibility.
If you’re exhibiting symptoms of metabolic syndrome, don’t panic. It’s very possible to undo the damage and regain your metabolic flexibility over time. Here’s how.
Being deficient in certain nutrients can cause your body to start losing its insulin sensitivity, resulting in metabolic syndrome in the long run. Prime candidates include zinc, chromium, [4], magnesium [8] and vitamin D [9].
Cymbiotika Zinc Complex is a blend of three forms of zinc. Bioptimizers Magnesium Breakthrough is a full spectrum formula with all 7 forms of magnesium. Bulletproof A-D-K packs vitamins A (as retinyl palmitate), D3, K1 and K2.
Working out is a sure way to improve your metabolic flexibility. Endurance exercise (think walking, hiking, gentle cycling) has been shown to improve mitochondrial health, while HIIT and other types of interval training can improve your hormonal status. [5]
Fasting is one of the fastest, most direct ways to become more metabolically flexible. Fasting essentially forces your body into fat-burning mode. More on how this works a little later.
Related: Intermittent Fasting for a Longer and Healthier Life
The keto diet reduces your body’s insulin production demands almost instantly. It also retrains your metabolism to burn fat for fuel. Most people experience fast weight loss on the keto diet, too, which further improved metabolic flexibility [10].
But perhaps the very best way to apply the ketogenic diet is through cyclical ketosis. This approach involves eating a larger amount of carbs (100-200 grams) once or twice a week. While eating carbs will momentarily kick you out of ketosis, it’ll also help your body stay sensitive to hormones like T3 and leptin. [6]
As we said above, fasting practically forces your body to burn fat for fuel. Studies hint that any type of fasting may foster metabolic flexibility, so it makes sense to opt for whichever type feels most sustainable — even enjoyable — to you.
Some of the most popular types of fasting include:
Intermittent fasting (IF) is probably the very most popular of all these approaches. That’s because it’s so approachable. Since the "easiest" version of IF only calls for as little as a 12-hour fasting window, getting into it can be as easy as just skipping breakfast. Although, strict IF calls for a 16h fast and an 8h "eating window". This is thought to provide the greatest benefits [11].
Time-controlled fasting prevents high fat diet-induced metabolic inflexibility in skeletal muscle.
Image source: ResearchGate
Most people opt to take things a little further by fasting for 18 hours of each 24-hour day, leading to an 8-hour eating window. That’s enough time to eat two big meals and a snack or two.
What’s particularly interesting about intermittent fasting is that not all of its benefits can be attributed to calorie restriction. Intermittent fasting may reverse metabolic syndrome even when compared to an isocaloric three-meals-a-day diet. [7]
Metabolic flexibility is one of the most foundational, farthest-reaching health metrics. With it you’re likely to enjoy a long, fit, mentally sharp life — without it, you’ll be far more likely to become obese, diabetic, and chronically ill.
Want to ensure that you stay metabolically healthy in the long run? Consider eating a nutrient-rich diet, partaking in exercise that you enjoy, and occasionally caloric-restriction. Your metabolism should be able to take things from there.
References:
1 - https://www.sciencedirect.com/science/article/pii/S0025619622000428
2 - https://www.heart.org/en/health-topics/metabolic-syndrome/your-risk-for-metabolic-syndrome
3 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3951818
4 - https://pubmed.ncbi.nlm.nih.gov/27854048/
5 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1540458/
6- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4251481/
7 - https://clindiabetesendo.biomedcentral.com/articles/10.1186/s40842-020-00116-1
8 - https://pubmed.ncbi.nlm.nih.gov/27834189
9 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6513299/
10 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7400909/
11 - https://www.sciencedirect.com/science/article/pii/S1568163718301478?via%3Dihub
Vitamin D and cholesterol are metabolically linked because cholesterol is a key precursor for the skin's synthesis of vitamin D3 when exposed to sunlight.
Cholesterol is a waxy substance found in all cells, essential for producing hormones, vitamin D, and bile acids that aid digestion. While high LDL (bad) cholesterol contributes to plaque buildup in arteries, cholesterol is necessary for many vital functions.
Magnesium may also be the key to unlocking deep, restorative sleep.
Insomnia, restlessness or night craps getting in the way of your sleep? These are signs of a magnesium deficiency.
Chronic stress, busy schedules, and excessive screen time before bed, millions of Australians struggle to get quality shut-eye. However, research continues to support the idea of a simple solution: getting enough of the essential mineral magnesium.
