Ever wonder how some people seem to have boundless energy while you wish you could have pushed the snooze button five more times? Why is your co-worker ready to take on the local mud run race this weekend while you’re planning to do some serious Saturday afternoon napping (not that there’s anything wrong with a good nap)? And how does your sister eat anything and not gain a pound? This is likely due to metabolic flexibility.

Metabolic flexibility is the body’s ability to switch between different types of energy production depending on what is available. Our bodies are amazing in that they have more than one process to produce the energy needed to keep us going. This enables continuous energy production to fuel basic metabolic processes, even during fasted states like that 3 PM afternoon slump.

Metabolic flexibility is kind of like choosing between premium unleaded or regular unleaded at the gas station. Our body’s most preferred state of energy production is glycolysis, AKA premium unleaded—when glucose (sourced from carbohydrates) is broken down into molecules known as pyruvates and ATP, or adenosine triphosphate, the fuel that provides energy to power our cells.

Lipolysis is the metabolic process that ramps up while we are fasting. It uses lipids, or fats, as an energy source, AKA regular unleaded. This enables our bodies to keep functioning—even during periods of starvation. Really, it’s quite an extraordinary survival tactic and ensures that basic body functions—like cell production, respiration, digestion, and our constant heartbeat—continues even when there is a lack of nourishment.

So why should we care about metabolic flexibility?

Metabolic flexibility can be a measure of our health. The more adaptable your body is during various metabolic states, the more efficiently your body operates. A metabolically flexible body can adeptly switch between glycolysis and lipolysis to prevent drops in blood sugar and conditions like hyperglycemia, where blood glucose spikes after eating. That flexibility tries to keep our bodies in a state of steady cruise control, instead of feeling like we’re in the Indy 500 one second and then riding in a horse and buggy the next.

However, metabolically inflexible people often cannot use fat oxidation for energy or they have disrupted systems. This can be a sign of insulin resistance, when the cells in the body have an impaired response to insulin and have difficulty managing excess sugar in the blood. This can be a precursor for diabetes and is often caused by what we call overnutrition. A constant supply of energy sources can upset our body’s flexibility to shift between the different energy modes. That’ll leave us feeling fatigued, skew our hunger cues, and, worse yet, increase our food cravings.

Metabolic flexibility is also vital to our endurance. The ability to shift seamlessly between “premium” and “unleaded” can make a big difference not just in our workouts, but also in our ability to make it through our busy days. Being able to tackle that big project at work, chase after our kids or grandkids, or run that 5K we’ve been working toward isn’t just important for our physical health, but super valuable for our mental and emotional health too.

So how do we build our metabolic flexibility?

Fix your relationship with food. Now. Develop a mindset that food is good for you and nourishes your body with nutrient-dense meals each day. Journalist Michael Pollan has written extensively about food and our health. He has advocated for avoiding foods, particularly processed foods, that “your great-grandmother wouldn’t recognize.” I would add in extra protein, especially for perimenopausal and menopausal women, but my sentiment is the same. Stick with whole, natural, nutrient-dense foods. Staying away from highly processed foods with added salt and sugar will do your metabolic flexibility good. (Learn more about how to fix your relationship with food and lose weight in 2025, join me at my free webinar, What to Eat to Lose Weight.)

And I would be remiss if I didn’t mention exercise. To build metabolic flexibility we want to improve our mitochondrial production. Mitochondria are the power facilities that charge our cells by converting ATP to energy. The more we exercise, the more we build our mitochondrial muscles. This builds our endurance, our capacity to use fat as an energy source, and the ability to shift between the different metabolic states to power through our days.

My programs can help support your metabolic flexibility. Try a strength training class with me, in person or virtually! Simply email schedule@adriencotton.com to sign up. Or commit to your health in 2025 by registering for my program 8 Weeks of Wellness.

SEE ALSO: My Five Favorites for Weight Loss and Maintenance