To Fast, or Not to Fast? That Is the Question, Bro

There are many heated debates in the bodybuilding community (as we've touched on before), and this one's a doozy: do you maximize your muscle-building potential by guzzling gallons of protein immediately before your workouts? Or do you go for the ultra-shredded, maximum-vascularity common with fasted workouts? Well, it isn't quite as cut-and-dry as all that. But we'll explain why this debate is still raging on in the fitness community - sometimes even in the face of contradicting evidence.

The Evidence for Fasted Workouts

The more scientists poke and prod us, the more we learn about how the human body actually works. While this may seem rude, it's actually a good thing. And the truth is that more recent studies actually have some good things to say about fasted workouts.

For starters, everyone who works out while fasted gets a metabolic boost to their insulin sensitivity. And when you're more sensitive to insulin, it helps the body become more efficient at metabolizing and utilizing the energy you put into it post-workout. It also helps athletes, especially endurance athletes, use their energy stores for exercise.

Next, fasted exercise (and fasting in general) sents your Growth Hormone levels surging through the roof. And the longer you fast, up to a certain point, the more benefits you reap. For example, a 24-hour fast can increase overall GH levels by 2,000% in men, and up to 1,300% in women (ladies).

The biggest takeaway from all of this, and many other studies, is that fasted cardio gradually transforms your physiology from "average athlete" to "beast mode" over time. Between regulating hormones like insulin, increasing testosterone and HGH, and improving how your post-workout meals get metabolized, there are many positive benefits to fasting before a workout.

Why the Haters Hate on Fasted Exercise

"Traditionalists" in the bodybuilding community are more likely to hold onto the idea that fasted cardio is bad, especially for muscle-building. In their defense, the science seemed sound back in the day when these theories were first proposed. But lots of scientific research in the interim has expanded our knowledge of how the human body works by leaps and bounds. Still, we feel the need to address some of their biggest concerns:

  1. Safety concerns. Is there a danger someone reading this article will try to fast too long, work out too hard, and injure themselves (or worse)? Obviously, taking your fasted workout past a certain extreme is very dangerous. If you're new to fasted exercise, start slow and gradually work up. Trust us - the results are worth the wait.
  2. Muscle catabolism. Some people like to cite studies saying that you catabolize more muscle while fasted than fueled. However, most of these "studies" only measure what your muscles do up to 195 minutes post-workout. While more muscle might get broken down in the short-term, it would be interesting to see how much muscle gets built back up during a longer recovery period (between 24-72 hours). Our experts have yet to see any studies on this.
  3. "Calories in vs. calories out". Most CIVCO people love to argue that "you're not going to burn fat in the first place if you aren't in a calorie deficit, so it doesn't matter whether you're fasting or not". But a recent study on gene expression in fat cells sheds some doubt on this idea. To make a long story short, fat cells are terrible at multitasking. They can't be used for energy and store your recently-chugged high-calorie protein shake at the same time. And when you force your fat cells to choose between one or the other, they are more likely to store energy and get fatter than they are to melt away - in the short term, at least.

The Best Way to Meet Your Goals: Find a Balance

If you really want that Huge Jacked-Man look, you're going to want to balance your fueled workouts with fasted ones in order to fine-tune your physiology. Some fueled workouts may help you break down less muscle, but fasted cardio is what you need to burn fat and optimize your total athletic performance.

Another way you can enhance your athletic performance is to try replacing a calorie-loaded pre-workout meal with Growth Factor instead. You'll get the metabolic benefits of a fasted workout, while also rushing muscle-building amino acids straight to where your body needs them most. It's a total win-win situation. And who doesn't like that?