Lifestyle Blog

Flexing Your Metabolism


by Scott Silveira, MS, R.C.E.P
Lead Exercise Physiologists
California Health & Longevity Institute

Metabolic flexibility is the body’s ability to switch between using fats and carbohydrates for energy. During times of fasting, the body uses fat as its main energy source, sparing carbohydrate stores for future use. Conversely, after a meal, fat metabolism is reduced as carbohydrate metabolism is used for immediate energy.

How is Metabolic Flexibility Measured 
Metabolic flexibility can be assessed with two special metabolic tests namely, the euglycemichyperinsulinemic clamp or via gas exchange (1). During these assessments, doctors will use insulin, sugar, or fat to determine how your body utilizes different types of energy sources.

Based off of the results of your metabolic profile, doctors, dietitians, and exercise physiologists can develop and customize nutritional and exercise protocols specifically for you. Having the right strategy can improve your success in weight loss or overall health goals.

Why does Metabolic Flexibility Matter 
Problems occur when this metabolic process is blunted. People with poor metabolic flexibility may be more likely to develop conditions like type 2 diabetes and obesity (2). While the exact mechanisms underlying type 2 diabetes and obesity are still unclear; we do know that overeating and physical inactivity are both culprits of these conditions and connected to the metabolic process.

Exercising your Metabolism 
Fortunately, our metabolic flexibility can be stretched and trained in three ways:
1. Avoiding foods high in sugar and refined carbohydrates
2. Increasing physical activity; both cardiovascular and weight bearing exercises
3. Extending the amount of time between the first and last meal of the day (3).


1. Galgani, Jose E, Cedric Moro, and Eric Ravussin. “Metabolic Flexibility and Insulin Resistance.” American Journal of Physiology, Endocrinology and Metabolism. 59.5 (2009). Print.
2. David, E K, He Jing, V M. Elizabeth, and B R. Vladimir. “Dysfunction of Mitochondria in Human Skeletal Muscle in Type 2 Diabetes.” Diabetes. 51.10 (2002): 2944-2950. Print.
3. Goodpaster, BH, and LM Sparks. “Metabolic Flexibility in Health and Disease.” Cell Metabolism. 25.5 (2017): 1027-1036. Print