Fasted Cardio: Everything You Need To Know

Fasted cardio is all the rage. When utilizing fasted cardio, you are engaging in your cardiovascular exercise before taking in any calories. In order to consider it fasted cardio, you need to have not eaten for eight to twelve hours. For most people, if they sleep a full night and get up in the morning and workout that would be fasted training.

Even though fasted cardio does not involve any food, it is highly advised that you take in some water before the workout.

Who Should Use Fasted Cardio?

fasted cardio truth

Although anyone can use it, it is especially valued by people trying to lose weight. The theory is that since your body is in a fasting state, in the absence of food your body has no choice but to burn the fat in your body.

In addition, fasted cardio is often used by athletes who are trying to train their bodies to use the fat stores. From a body efficiency perspective, the goal in this is to be able to plug along during endurance events even when tired or running low on fuel. The idea is that this tactic will help prevent an athlete from “bonking” during a race.

Does Fasted Cardio Actually Work?

Although many people swear by it, science shows mixed reviews. On the one hand, fasted cardio does seem to burn more calories and fat during the workout than cardio done with a fully fueled body. It burns up to 20% more fat, in fact! However, the question remains if the overall impact is long-lasting and beneficial.

It seems that science does not substantiate the belief that an individual who works out fasted burns more calories throughout the remainder of the day. In fact, some exercise physiologists actually strongly feel that it is detrimental.

Benefits of Fasted Cardio

In addition to the idea that you will burn more calories and/or fat, there are other benefits to fasted cardio.

First, you won’t experience abdominal discomfort that comes with workouts on a full belly. We have all been there: you eat your breakfast, head to the gym, and your tummy starts to ache. When doing fasted cardio, there is none of that.

Second, you don’t have to worry about life getting in the way and not getting a workout in. With this type of cardio, you are typically working out as soon as you roll out of bed.

Does Fasted Cardio Burn Muscle?

Although some people worry about fasted cardio burning muscle instead of whatever food they may have consumed, it does not seem to be the case. So if you are looking at muscle growth from a bodybuilding perspective, don’t obsess about fasting cardio unless it’s a personal preference for you as an athlete.

How Long After Fasted Cardio Should You Eat?

Upon completing a workout, you should take in nutrients. Whether your workout is fasted or not, you should be eating something within 45 minutes. And unless you want to undo the good you have done, post-workout snacks or meals should be deliberately planned.

If you are trying to have balance in your nutrition, your post-workout meal or snack should have protein, carbs and fat components.

Your carbs should not be junk, however. When thinking about refueling the body, consider what “real fuel” looks like. Anytime you can consume food in its most natural form you are doing your body a service. Some natural carbs are sweet potatoes, grains like quinoa, fruit, leafy green vegetables, and steel-cut oatmeal.

natural carbs

Protein can come in the form of lean meats, eggs, greek yogurt, cottage cheese or other options. Healthy fats such as avocado, nuts, and nut butters are great choices.

Because it isn’t always handy to have all of these real food items at your disposal, many people prefer easy, portable recovery foods and beverages. This is why protein bars and powders to make drinks are so wildly popular.

Why is a Post Workout Snack Important?

When you workout, your body depletes glycogen stores for fuel. You need to replenish these stores so your body keeps moving along like the well-oiled machine that it is.

Upon completing a workout, your body needs to replenish these stores in order to repair muscles. You will not only repair muscles but you will also enhance your recovery.

Downsides of Fasted Training

One big downside to fasted training is that until you acclimate, you may find you aren’t able to work out as hard. Some athletes report they are running slower or lifting less. It does seem, however, as if most athletes do eventually get used to this and pick up the pace yet again.

There is also an increased risk of “bonking” or hitting the wall if training in a fasted state.

Is Fasted Cardio Dangerous?

Perhaps dangerous is too strong a word, but perhaps it isn’t. For example, for an endurance athlete such as a distance runner or cyclist, fasted cardio could be dangerous. If you are running alone early in the morning and find yourself with low sugar, that could prove dangerous.

fasted cardio benefits

Athletes are encouraged to be smart and safe if using fasted cardio, especially if it is a new thing to the individual. Anyone considering trying it should start with a shorter distance, bring some sort of simple sugar on the training route and maybe bring a training partner.

Less worrisome is a person trying fasted cardio in a gym where there are others around, should they end up in trouble.

Does It Work?

There really are differing opinions on fasting cardio and the thing with data is that it can be slanted to prove either side of an issue. This author and avid runner feels that the research does not adequately present the case for fasted cardio from a fat and calorie burning perspective.

If your body performs well on no fuel, fasted cardio may be a fine decision for you. However, the benefits don’t appear to be strong enough to make a case for every athlete pushing themselves to achieve this type of workout on a consistent basis.

We have said it once and we will say it again: working out truly is a personal journey and each athlete needs to figure out what works for him or herself. Whether or not you eat before a workout is far less important to the fuel you put into your body for the rest of the day.

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