What is Fasted Cardio?

Will Cardio On An Empty Stomach Accelerate Your Weight Loss and Fitness Efforts?

Fasting in general is a somewhat controversial subject. Either experts are against it or support it being done as part of an overall wellness regime. Depending on what you are trying to achieve, periodic fasting may actually boost your results. There are some studies and books out now that are all about the potential benefits of fasting from time to time.

One very popular exercise for fat loss is fasted cardio. This technique is by no means new, but it is once again entering the spotlight as some of today’s popular diets actually favor intermittent fasting.

What is Fasted Cardio and How Does It Work?

Fasted cardio is essentially any type of cardiovascular exercise done on an empty stomach. The only difference between regular cardio and fasted cardio is the fasting portion. You can continue doing your regular cardio routine, just skip breakfast and workout first thing in the morning.

The theory behind fasted cardio is that your body will burn fat stores since your stomach is empty. The human body will first use up energy from the food it’s recently consumed, so if that isn’t available it must get its energy from storage. One study featured in the British Journal of Nutrition showed that those who practiced fasted cardio burned 20% more fat than those who had eaten.

“Fasted cardio in the morning is effective because as you sleep and fast overnight your body conserves its precious carb stores and leans toward mobilizing fat for fuel. The story doesn’t end here, however. Your body also breaks down amino acids into glucose overnight, so fasted morning cardio mobilizes more fat and potentially more amino acids for fuel, which isn’t ideal if building muscle is your primary goal. This isn’t a huge problem as long as you consume a fast-digesting protein like whey, along with some slow-digesting casein, after your cardio.” – More great info on this topic from Bodybuilding.com

However, there have been other studies that show no change between fasted and fed participants. Additionally, this study showed that fasting prior to exercise may negatively affect performance as the day goes on.

While there have yet to be studies done specifically on the effects of fasted cardio on trained athletes, many personal trainers have theories that this type of exercise is best suited for those who are already fit. While very little change from fasted cardio may be witnessed in people who are severely overweight, this little change can mean all the difference for a person with low body fat needing to fix some trouble areas.

Deciding whether you should do fasted cardio is really up to you. If you already have a low body fat percentage but are having trouble slimming your thighs, working out on an empty stomach may be just what you need. If you are just beginning your weight loss journey and are 20+lbs overweight you may feel disappointed if you fast and don’t notice increased results.

My advice: Do your cardio workout when you can and focus more on the intensity of your workouts!  If fasted cardio works for you, great.  If it doesn’t, you can still lose weight.  What you EAT in terms of healthy food is more important in terms of the overall weight loss equation.

Is Fasted Cardio Safe?

Like almost every exercise technique or regimen out there, fasted cardio could be unsafe for some people. If you are going to pass out if you don’t eat at least 30 min before you workout…then that’s a problem. If not done properly you could lose muscle mass, cause potential physical damage or simply just burn yourself out by being tired and feeling weak when exercising.  It’s not for everyone…but it’s also not new and there are tons of people who will tell you that it’s perfectly safe and they’ve done it for years.  I can’t tell you for sure.

Some important tips to keep in mind include:

• Don’t do fasted cardio if you are feeling hunger pangs.
• Don’t do fasted cardio if you are pregnant.
• Don’t do fasted cardio if you have a serious health concern like diabetes. (Talk to your doctor about how to maximize your fat loss with exercise.
• Drink water before, during and after your cardio workout.
• Your next meal – Aim to drink an easily-digestible protein shake right after your cardio or a meal with protein.
• Eat a good meal 2 hours before bed if you plan to do a fasted cardio session the next day.
• Take the time to properly warm up and cool down.
• Fasted cardio works best when you on a very structured eating regime that keeps your fasted cardio in mind so that you are well fueled all day.

It is important to listen to your body when trying out any new type of exercise. If you don’t feel right during or after exercising, such as fatigue or excessive soreness, stop what you are doing and reevaluate your technique. Some people simply find that fasted cardio doesn’t work for them and can actually hinder their results. Don’t force yourself to do something just because other people get results as you may end up harming your body.

How Can I Start Doing Fasted Cardio?

The easiest way to start doing fasted cardio is to knock out that portion of your workout in the morning. Since your body is in a fasted state within 8 to 12 hours of not eating doing this exercise before breakfast is ideal. After your cardio workout it is a good idea to wait an additional 30 minutes before eating a real breakfast, but you can grab a protein drink or make a low calorie protein smoothie. Once you do eat breakfast you should eat a meal high in protein to help replenish your muscles.

Fasted cardio is a simple concept that many find to be beneficial, if done right, for fat loss. It may be especially helpful for those who have hit a plateau or want to really tone up before an event. Keep the tips on safe fasted cardio in mind and if you ever feel weakness or as though you are losing muscle, stop.

More info:

• Is Fasted Cardio Best for Fat Burning?
• Does Fasted Cardio Really Burn More Fat?