Fasted Cardio – Does It Really Work?

“Fasted Cardio” is exercising when your body has no food reserves in the belly or the digestive tract. Most who participate in fasted cardio do so in the morning. It takes 6 to 8 hours to totally empty your digestive system. So a full night’s rest should do the trick.

The theory behind fasted cardio is this: the body is forced to use fat stores for energy because there is no food (carbohydrates) currently in it’s system. Long term practice of fasted cardio trains the body to regularly pull from fat stores for energy. Fasted training gets a lot of hype in the fitness world but wouldn’t it be nice to know if its actually doing what we’ve been hearing?

Fitness Buffs Claim That You Can Experience The Following Benefits From Exercising In A Fasted State

Here’s What Actual Studies Have To Say

So many of the people out there who promote fasted cardio are young and in really great shape already. We don’t see many averages joes boasting about their weight loss success thanks to fasted cardio. Without a broad example of fasted cardio from people of many ages, heights, and body composition, determining whether or not fasted cardio burns more fat than traditional cardio is nearly impossible.

However, one study sums things up pretty well as we consider everything we’ve read so far about fasted cardio:

“…the effect of fasting on energy levels during exercise ultimately has an effect on fat burning. Training early in the morning on an empty stomach makes it very difficult for an individual to train at even a moderate level of intensity. Attempting to engage in a HIIT style routine in a hypoglycemic state almost certainly will impair performance (33). Studies show that a pre-exercise meal allows an individual to train more intensely compared with exercise while fasting (25). The net result is that a greater number of calories are burned both during and after physical activity, heightening fat loss…the literature does not support the efficacy of training early in the morning on an empty stomach as a tactic to reduce body fat. At best, the net effect on fat loss associated with such an approach will be no better than training after meal consumption, and quite possibly, it would produce inferior results.”

The study also describes other effects that fasted cardio has on the body besides fat burning that are worth considering before beginning a program that involves fasted training.

In theory, if you could train in a fasted state and still put forth the same effort as you would had you eaten before hand, you might be able to burn more fat. BUT few people can maintain the same output for cardio in a fasted state.

Where do you lie?

If Your Feel These Symptoms During Fasted Cardio, Stop.

Fasted cardio is tricky. It can take time getting used to pushing your body to the limits without eating before hand. So its important to pay attention to the way you’re feeling. While you may know lots of people who do fasted training, that doesn’t mean its something that everyone should be able to do. There are a few symptoms you could (and probably will) experience when you first begin fasted training:

“Bonking” is an actual term used by athletes to describe feelings of lethargy or light-headedness when exercising. This is usually due to low blood sugar. If you’re feeling this way, grab a snack to boost your blood sugar levels. You should be feeling better in a matter of minutes.

Fasted cardio may be dangerous, depending on your current state. Adults over the age of 55, those with Diabetes or other pre-existing health conditions could be at higher risk for “bonking” during fasted cardio. No matter who you are, speak with your doctor about fasted training to see if that’s a wise option for your weight loss goals.

Overall, studies show that fasted cardio can burn 20% more body fat during a workout than when you’re exercising with food in your system.

There Are Some Risks To Fasted Cardio

One theory concerning downsides to fasted cardio is the idea that the body enters “survival mode” when you restrict calories. This could, in turn, result in burning fewer calories to preserve energy. But this theory seems to go against the laws of thermodynamics and our basic understanding of energy expenditure. It’s like saying that normally a pushup would expend 25 calories but in a fasted state, your body only needs 20 calories to perform a pushup.

Fasted cardio can also be potentially dangerous for anyone with diabetes or other preexisting health conditions. Before beginning a fasted cardio routine, talk with your doctor.

Fasted Cardio – Are the results guaranteed?

No, they aren’t. While you may see more rapid fat loss by performing fasted cardio, you may not. In fact, it seems more likely that fasted training will result in faster fatigue, less intense efforts in your workout, and “bonking”.

Some swear by fasted cardio while others don’t. Some studies have found tidbits of positive correlations between fasted cardio and weight loss. And then you have a lot of studies out there that can’t positively identify a link between fasted cardio and any substantial health benefits. So it looks like the jury is still out.

Want A Proven Way To Reduce Body Fat Faster? Try This.

Alternate day fasting (ADF) has shown to benefit weight loss in obese study groups.

A plethora of studies support HIIT as a way to burn fat more rapidly than traditional endurance training.

Other Reading You Might Be Interested In:

How To Run Faster — Tips To Increase Your Speed

Workout Tips — Cardio or Weights First?

5 Reasons Why Running On A Treadmill Will Not Help You Lose Weight

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