Fasted Cardio

Morning workouts are amazing. They are convenient and supply you with energy for the rest of the day. But let me ask you this: did you know that you can speed up your fat loss by doing your cardio fasted? It’s true and here’s why.

Fasted Cardio Aids Fat Loss

Exercising fasted is one of the best ways of maximizing fat loss. Fasted workouts boost fat oxidation, which means you use more fat for fuel 1-2.

This has to do with insulin. When you eat, insulin levels rise and remain elevated for hours 3. This helps store the nutrients you consumed.

That’s great, but it comes with a downside: elevated levels of insulin impair fat oxidation 4. In other words, you burn less body fat and dietary fat. Instead, you’ll use more glucose (carbs) for fuel.

And what happens when you’re in a fasted state? The reverse: your insulin levels are lowered and you burn more fat. One study found that men burned nearly 20% more fat when they ran on an empty stomach compared to a post-breakfast run 5!

Will Fasted Cardio Eat My Muscle Away?

A common argument against fasted cardio is muscle loss. Some believe that since you don’t consume protein beforehand, your body will break down muscle tissue and convert it into amino acids (protein).

Well, that can be true if you hit your workout long and hard and lack sufficient protein intake in general. However, you’ll be fine if you keep your cardio sessions below the 60-minute mark and consume enough protein in total, which would be at least 0.8 gram daily per pound of body weight. In this way, you will not burn away your hard-earned muscle tissues.

But what if you do intense cardio sessions longer than 60 minutes? In that case, consume 10 grams of BCAAs before your workout. It will not interfere with your fasted state, but it will prevent muscle loss.

How To Get Started

So, are you ready to take your cardio session to the next level and maximize fat loss? Great! If you’re new to fasted workouts (or fasting in general), the first sessions might be challenging. Food cravings and impaired performance are common, but don’t let that derail you – your body will adapt after a few sessions. You’ll feel less hungry, your performance will improve and, hopefully, you will start seeing changes in the mirror.


1. Derave, W., Mertens, A., Muls, E., Pardaens, K., & Hespel, P. (2007). Effects of post-absorptive and postprandial exercise on glucoregulation in metabolic syndrome. Obesity, 15(3), 704-11.

2. Van Proeyen, K., Szlufcik, K., Nielsen, H., Ramaekers, M., & Hespel, P. (2011). Beneficial metabolic adaptations due to endurance exercise training in the fasted state. Journal of Applied Physiology, 110(1), 236-45.

3. Surina, D. M., Langhans, W., Pauli, R., & Wenk, C. (1993). Meal composition affects postprandial fatty acid oxidation. American Journal of Physiology, 264(6;2), 1065-70.

4.. Choi, S. M., Tucker, D. F., Gross, D. N., Easton, R. M., DiPilato, L. M., Dean, A. S., . . . Birnbaum, M. J. (2010). Insulin regulates adipocyte lipolysis via an Akt-independent signaling pathway. Molecular and Cellular Biology, 30(21), 5009-20.

5. Gonzalez, J. T., Veasey, R. C., Rumbold, P. L., & Stevenson, E. J. (2013). Breakfast and exercise contingently affect postprandial metabolism and energy balance in physically active males. British Journal of Nutrition, 110(4), 721-32.