By Shelby Stoner, PHASE IV Exercise Physiologist
To fast, or not to fast? This seems to be a question circling around the fitness industry in recent years, referring to the trend of “fasted cardio,” often performed by working out in the morning on an empty stomach. For most of us, getting out of bed in the morning is hard enough, let alone getting in that early morning workout. If you’ve been toying with the fact of fasted cardio lately, you may want to read more about how it may or may not be right for you.
It’s no secret that scientifically driven nutrition and exercise programs are essential for maintaining good health, losing weight, or increasing athletic performance. However, the measures we take to get there vary greatly from person to person. Many athletes, bodybuilders, and fitness enthusiasts in general promote the idea of “fasted cardio,” i.e. performing cardiovascular exercise while on an empty stomach and in theory maximize fat burning.
Many of our clients often ask if fasted cardio in the morning is the best way to burn fat. Short answer? Yes ... and no. When it comes to the physiology of the human body, especially during exercise, nothing is simple.
First, let’s go back to the basics: Fat metabolism is regulated by your body’s ability to break down fat and use it for fuel. The efficiency at which your body is able to use this fat for energy largely depends on your training status and current fitness level, and here’s why.
Our muscles store carbohydrates in the form of glycogen which is used by the body as needed. The body naturally prefers to break down carbohydrates (aka glucose) as it is readily available, easy to break down, and provides a quick source of energy. That’s why when exercising; it is the act of draining the muscle cell of carbohydrates that forces it to increase its ability to use noncarbohydrate fuel sources such as fat. This is primarily accomplished by performing Long Slow Distance (LSD) exercise that depletes the muscles of glycogen and forces the body to draw from our fat stores. As a result, we enhance our fat-burning metabolism and teach the muscles to store greater amounts of glycogen which allow us to exercise longer, fight fatigue, and recover faster.
Some studies do show that fasted cardio in the morning may burn up to 20 percent more fat; again, this is largely determined by your fitness level. Individuals who are active on a regular basis benefit more from fasted cardio as they have trained their metabolism to shift from preferring carbs to fats for fuel. For the trained individual, fasted cardio in the morning is effective because as you fast overnight, your body conserves its precious carb stores and leans toward mobilizing fat for fuel.
However, despite the evidence above, we can't unequivocally say that fasted cardio is the best form of training for everyone. This is because the real benefits of exercise come after training. While calorically fasted cardio may or may not be effective for you, training in a lower carbohydrate state may be beneficial for optimizing the preference of fat as a fuel source-if you do it right! In general, fasting is OK, but being low-carb may be equally, if not more important if your goal is fat loss.
So, if you're like most people, your best bet is to not worry about doing cardio fasted first thing in the morning. If doing cardio first thing in the morning is best for your schedule, then go for it, but make sure to drink at least 8-12 oz of water and other fluids beforehand.
Take away message: Fasted cardio may provide benefits such as increased fat burning, but there is a time and place for it. It will not provide optimal benefits unless you have already trained your metabolism to prefer fat as fuel. If you do perform cardio on an empty stomach, make sure to drink fluids and refuel after your activities. And rather than worrying whether to eat or not, focus on what you should be eating.
At PHASE IV, we have the knowledge and expertise to help shift your metabolism to burn fat all day long supporting your weight loss and performance related goals.
To learn more, schedule a FREE health and fitness consultation today at (310) 582-8212 or email me directly at firstname.lastname@example.org.