Is Fasted Cardio the Key to Fat Loss?

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Fasted Cardio for Fat Loss

Fasted cardio: The idea that when you exercise is as important as what you do.

Do you eat before you exercise? Most of us do, especially when we're attempting to complete an intense cardio session. But what if switching the order could help you to lose weight more quickly without having to take one more step?

Recently, the New York Times reported on a 2010 Belgian study that showed fasted cardio kept test subjects from gaining weight even when they were eating an unusually high-calorie, fatty diet. The article suggested that if you got a little tipsy last night and ate an extra large Papa John's with three extra garlic dipping sauces (I've NEVER done that, I swear...), maybe fasted cardio was a good way to do damage control. This is incredibly appealing to all us overachievers out there. I mean, it logically follows that if you don't change your diet AND do fasted cardio, you're bound to lose weight really quickly, right?

What's the Deal With Fasted Cardio?

Fasted cardio is cardiovascular exercise that's usually performed in the morning before you eat breakfast. All it really means is that you're exercising after a long fast, which naturally happens first thing in the morning.

When you eat, your insulin levels rise. Insulin inhibits lipolysis and fat oxidation, or fat burn. This means that your body burns fat more quickly when you're running on an empty tank. The idea is if you combine that with cardio, you can burn more fat and calories than if you did the same amount of exercise after eating.

Sounds incredible, right? All you have to do is set your alarm a little (ok, a lot) earlier and you can kiss your love handles goodbye. And a lot of people swear by fasted cardio. It's long been a technique used by body builders to lean out before competitions, and right now its popularity is in an upswing among fitness enthusiasts and casual exercisers alike.

Fasted Cardio or Busted Cardio?

Although fasted cardio makes an exciting and proven claim, things are a little more complicated than that. Your body doesn't exist in a vacuum when you're not exercising. It's burning calories all day. Fasted cardio critics argue that if you don't have enough fuel you won't really be able to pull off an intense workout. Therefore, your EPOC, or the afterburn effect, where your body burns calories and fat at an accelerated rate after exercise, will be substantially less. The more intensely you exercise, the greater your EPOC will be. So, a really tough workout is going to burn fat and calories long after you've stopped exercising.

A 1999 study published in the Journal of Sports Medicine and Physical Fitness showed that participants who ingested glucose before exercising increased their EPOC more than those who exercised in a fasted state. The study also showed that high intensity, short duration exercise increases fat burn during the recovery period more than low intensity, long duration exercise.

So, if you only have enough gas in your tank to do a long slow run in the pre-dawn dark, are you really burning as many calories and as much fat as you could if you had enough get up and go to crush an hour long HIIT workout after some bacon and eggs? And which one sounds like more fun?

My Two Cents

I've never tried fasted cardio myself and I was really curious. So, for two weeks, 3 days a week, I got up at 5:30 a.m. to do 20-30 minutes of intense, almost-barfing style, fasted HIIT cardio. On those days I didn't do any more cardio, which is unusual for me. I ended up doing a lot more heavy lifting just because I had so much extra time. And I definitely saw a difference in my body. The little ring of flab I usually carry around my middle disappeared. And because I was devoting so much more time to lifting, my muscle definition was much more apparent. I also think that because I was doing less than half of the usual amount of cardio I usually do, I was able to retain more muscle.

But. It was really hard. I didn't feel great while I was doing the FC. It was inconvenient with my kids' schedules. And all during those two weeks I felt kinda blue. I dreaded getting up for the workouts. Every night after FC I fell asleep on the couch. A friend came over for a late dinner and I was a zombie. I missed my cardio classes and my friends and teachers. I missed the high I got from making a bonkers #sweatpool under the stair climber or elliptical machine while getting swept away by Beyoncé.

Where's YOUR Finish Line?

While I do believe that fasted cardio can be effective, I think that there are so many variables you have to consider. What kind of cardio are you doing? How hard and often are you doing it? Are you lifting weights? If you are eating before exercising, what are you eating? And what are you eating for the rest of the day? All of these things affect how your body looks, functions, and feels.

And let's consider goals. Personally, I want to be strong, lean, and enjoy exercise. And I'm so much more likely to skip a workout that's not pleasurable and inconvenient. But if you're struggling to lose stubborn fat, want to look crazy in your bikini for that cruise, or just want to take things to the next level, fasted cardio could be a great addition for you.

Remember, always take the proper precautions and exercise smart. Stay hydrated and safe. Don't run 10 fasted miles and get stuck somewhere weird in the dark and pass out. If you're a fasted cardio beginner, take a banana and a friend with you, just in case. And above all, have fun out there.

Happy workouts are the best ones!

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Image: Woman Running Photo from Shutterstock

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