So you want to lose fat, I mean - who doesn’t?
No problem, losing fat is easy, right? Not so much.
Chances are that you’ve probably seen countless ads for how to lose weight fast, products that claim to drop weight rapidly, or even change your body entirely in a short period of time. Obviously, it’s not that simple - otherwise, you wouldn’t be reading this.
Fads, a term used to describe enthusiasm around unsubstantiated methods or products, are, unfortunately, a normality in the world of fitness. Self-proclaimed fitness experts, gurus, and influencers alike spend their days preaching their “secrets” to their success in the fitness world. While in reality, many of these people are just blessed with outstanding genes that enable them to look and perform better than the average person without having to do anything special. Now, this is not the case for all established fitness professionals, as many of these people work incredibly hard for what they do and are very well educated. Another key point, just because something seems to work for you, it does not mean that it works for everyone. There is an immense difference between understanding how to achieve positive results for yourself and how to facilitate the success of others - which is why there are numerous options for obtaining the proper certifications to do so.
Why do I say all this? Well, in all honesty, I hope that if you take anything from this article, it’s that you understand that you need to educate yourself on what really works - what is backed by science, and what doesn’t. The ability to research these types of things on your own, and understand them, will serve you immense success. I tell you this now because I wish that there was someone who once told me this before I learned to do these things on my own. Of all of the different fad diets, workout equipment, and promising methods that I have tried over the course of my life - Fasted Cardio was the most useless of all of them.
The principle around fasted cardio is simple. By performing your aerobic exercises in the morning, on an empty stomach, you maximize your body’s ability to lose fat. Sounds cool right? Sure, in theory. So let’s ask ourselves this, What was the initial research that led to this theory of superior fat loss and what causes fasted cardio to - reportedly - be more efficient? In 1999, Bill Phillips published his famous Body-for-LIFE, an apparently groundbreaking piece of work that claimed to hold the keys towards transforming the human body. More specifically, a large focus was placed on his chapter that spoke on cardio. Phillips theory was that a the absence of food over an extended period of time would result in a reduction of circulating blood sugar. This would then cause glycogen levels to fall. With your body being depleted of its glycogen storages, your body then switches to a heavier reliance on stored fat as a source of energy as opposed to glucose. With that, he described that the low insulin levels that occur in a fasted state would increased the availability of fatty acids to be used as the fuel for your workout. Seems legit, right? I mean, who wouldn’t want to burn fat easier?
Truth is, Phillips was wrong. Fasted Cardio enthusiasts and bodybuilding coaches alike are most likely gritting their teeth while reading this - good, I hope they’re listening. The fact of the matter remains that studies that have been conducted on fasted - low intensity cardio (such as jogging or walking) have shown that there were no differences, between the fasted and fed cardio groups, within the first 90 minutes of the subjects involved in the study when talking about the amount of fat being burned. The only time that fasted cardio showed to have a slight advantage over fed cardio, in terms of fat oxidation, was after 90 minutes of sustained cardio. In other words, for fasted cardio to have any advantage over fed cardio, you’d only start seeing those very, very slight changes after you’ve hit the 90 minute mark of continuous low intensity cardio. Additionally, when you consider the effects of Excess Post-Exercise Consumption, commonly known as EPOC, fasted cardio shows no advantage over fed cardio - even after the 90 minute mark has been reached. This is because EPOC represents the amount of calories expended after training. When performing in a fasted state, EPOC is much lower than the increased levels of EPOC that result from fed workouts. This means that although fasted cardio burns more fat after 90 minutes of continuous exercise, it does not burn nearly as much nor does it keep burning for as long after the workout as that of fed cardio.
Even more damaging to the case of fasted cardio is the fact that fasted cardio has been shown to have a catabolic effect on muscle. When your body trains in a glycogen-depleted state, you burn significantly more muscle to be used for energy. This can be upwards of 10 percent of the total calories burned in a one hour cardio session. That means that in one hour of fasted cardio, you have not yet reached the length of time required to gain a slight advantage in terms of fat loss, however, you have been burning a significant amount of muscle throughout the course of the hour. You may be thinking, I’ll just drink my BCAAs, that won’t break my fast. Well, truth is, that won’t work either. I’m not sure what breaking your fast entitles, but you are offering another source of energy to now use instead of fat oxidation - thus delaying or even neutralizing the delayed effects that fasted cardio offers.
So, where are we? Well, in reality, we are stuck at a crossroads between two main questions. Can we do fasted cardio? Sure, of course we can. If you’re willing to sacrifice your hard earned muscle tissue for a very slight or non-existent advantage, go for it. But the second question being, “Should we do it?”, is a much better route to take. When asking ourselves ,“Should we do it?”, it comes down to one final question. Since you can receive the same results, if not better in the long run, from fed cardio, then why should we ever do fasted cardio? Unless you are a bodybuilder that is specifically trying to cut muscle in addition to fat, with the worry of being too muscular for your division, there is no reason that you should be doing it. The scientific research pertaining to fasted cardio doesn’t give it any support. In fact by doing this, you are missing out on of your body’s most crucial anabolic windows. Upon waking up, the anabolic effect of a high protein meal before doing anything else in the morning is one of the most impactful moments of the day when speaking on nutrient timing and the muscle building response that occurs when you use a fast acting protein to supercharge your morning. Remember, the more lean muscle tissues that you have, the more efficient you will be at burning fat, which is yet another reason as to why fasted cardio is counterintuitive to fat loss.
What do I hope you take away from this?
If fat loss is your goal, stick to methods that are proven. Skip out on fasted cardio and replace it with fed cardio. Stay away from ketogenic or no carb diets - they don’t work when compared to diets with the same amount of total kcals, in fact, if someone is still getting bigger and stronger on this type of diet - it’s likely because of performance enhancing drugs. (I’ll be posting about these types of diets in my next post). Lastly, do your research or consult a professional before starting a new method like this, just because someone has a lot of followers online or because your buddy who looks good does not mean that it is the best method.
Stop focusing on the easy way, and start focusing on the efficient way.
Author:
Joshua Horn - Master Personal Trainer, Strength & Conditioning Coach, Bodybuilder, Marine Corps Infantry Veteran, Redcon1 Athlete.
Instagram: https://www.instagram.com/joshthehorn
References:
https://www.nsca.com/education/videos/physique-versus-sports-nutrition-are-they-contradictory/
https://www.bodybuilding.com/content/the-myth-of-cardio-before-breakfast-debunked.html
https://pubmed.ncbi.nlm.nih.gov/9831734/
https://pubmed.ncbi.nlm.nih.gov/7380688/