For the most part, there are two types of active people. Those who enjoy an early morning workout, and those who don’t.
If you’re a person who trains first thing then you’ve probably spoken to somebody about fasted cardio or strength workouts. Basically, the conduct of physical activity and elevating your heart rate without eating anything in the last 8-16 hours. Hence the term fasted training.
Whilst most people who train very early may be already be doing this, many people will eat something before a workout, mainly because humans are creatures of habit and have been conditioned to believe that breakfast (or breaking the fast) is to be consumed first thing in the morning.
Intermittent fasting does take a little getting used to, whilst the adaptations are taking place to condition the body not to expect food at regular intervals.
Defining a fasted state
A true fasted state will generally begin in the vicinity of 8-10 hours without the consumption of any calories. However, the body can actually be in a fasted state as early as 5 or 6 hours after a meal.
The idea is that exercising in a fasted state forces the body to tap into its own energy reserves (stored body fat and muscle glycogen), as opposed to energy that has just been consumed, usually in the form of carbohydrates.
Fasted training
Now before you go and run off to the next sunrise there are a few things to consider prior to trialing fasted workouts.
Whilst fasted training is safe and actually a natural process, it will take time for the body to adjust to the idea that it will be conducting physical activity without any fuel. So start off by keeping the intensity relatively low so that the body doesn’t jump straight into an anaerobic state where is it chasing glucose for a quick energy source.
By the keeping a lower intensity, you will be allowing the body the appropriate time to access stored body fat and convert it into the energy it requires. Over time the body will become more efficient at these conversions, allowing you to workout at higher intensities, more quickly and for longer durations.
A point to note. The conduct of fasted workouts not only converts stored body fat and uses it as energy but can also break down stored proteins in the form of lean muscle. For most people exercising, this is not an ideal scenario.
This can be mitigated by drinking some branched chain amino acids (BCAA), before or during the workout. For most people, a serve of approx. 10g pre-workout should be enough to preserve lean muscle mass. Whilst technically not fully fasted, the total calories consumed in 10g serve of BCAA is approx. 50g, which would have a negligible effect on breaking a fasted state.
Bottom line
Fasted training is not for everybody. It does take time for the body to adjust, depending on how dependant you are on consuming sugars. This discomfort usually will pass in time, but if fasting in general isn’t for you, there is no need to keep it up.
Remember, the human body has evolved over millions of years in an environment where it has been forced to exert itself physically and mentally in times of both food scarcity and surplus. This is a totally natural process.
Once the body re-learns to operate and exert itself without any food, it will get better at performing when it does have fuel in the tank.
David Marcato 