Benefits Fasted High Intensity Interval Cardio

Fat Targeting:

The Benefits of Fasted High Intensity Interval Cardio for Fat Melting

By Maximilian Angle

Clients and friends often ask me what my preferred form of cardio is, and my reply always is, “I prefer fasted cardio.” This is not just my personal preference but also is backed up through studies and “in the trenches” research. When it comes to the biochemistry/physiology of the human body and how one person reacts to a specific type of training vs. another, it isn’t simple. Cardio first thing in the morning on an empty stomach is effective because as you sleep and fast overnight your body conserves its precious carb stores and activates the utilization of fat for fuel. The process doesn’t end here, however. Your body also breaks down amino acids into glucose overnight, so fasted morning cardio mobilizes more fat and potentially more amino acids for fuel, which isn’t ideal if building muscle is your primary goal. This isn’t a huge problem as long as you consume five to ten grams of branched chain amino acids along with 5 grams of L-glutamine before training.

Despite numerous studies and my opinion as stated above, we can’t unequivocally say that fasted cardio is best option for burning fat for everyone, or in general. Many studies on “fasted” or “fed” cardiovascular training focus solely on how many calories are burned during the exercise performed. This is biologically problematic because the real benefits of exercise, specifically high-intensity cardio and weight training, come after training. High-intensity training burns more calories and fat after a workout than low-intensity cardio due to its ability to increase the metabolism, and prolong the fat burning process. With high-intensity interval training (HIIT), you burn calories for several hours after training commences, even when you’re at rest.

Studies show that HIIT workouts which take less than half the amount time of slow-and-steady state cardio workouts lead to as much as twice the fat lost as a result of non interval training. Even though the slow-and-steady cardio programs burned more total calories and fat during the workout itself, HIIT programs somehow lead to greater total fat loss. This is because the HIIT workouts burned more calories and fat the rest of the day through an accelerated metabolism, which adds up to more calories and fat utilized than you can burn during a single workout.

An article on fasted cardio appearing in the Strength and Conditioning Journal by Brad Schoenfeld, MSC, CSCS states: “it is shortsighted to look solely at how much fat is burned during an exercise session. The human body is very dynamic and continually adjusts its use of fat for fuel. Substrate utilization is governed by a host of factors (i.e., hormonal secretions, enzyme activity, transcription factors, etc), and these factors can change by the moment. Thus, fat burning must be considered over the course of days—not on an hour-to-hour basis—to get a meaningful perspective on its impact on body composition. As a general rule, if you burn more carbohydrate during a workout, you inevitably burn more fat in the post- exercise period and vice versa. It should be noted that high-intensity interval training (HIIT) has proven to be a superior method for maximizing fat loss compared with moderate- intensity steady-state training.”

So, if you’re unlike most people, your best bet for a successful fat loss program in my opinion about doing cardio fasted first thing in the morning, is to utilize both for their symbiotic benefits. If doing cardiovascular exercises first thing in the morning is the optimal fit for your schedule, then I applaud you to do it, but try to at least have a pre-workout branched chain amino acid drink, especially if your primary goal is muscular hypertrophy. But this is all a matter of opinion and there is no one solution. I recommend you try everything and discover for yourself what works best for you.

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