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One Workout Trick That's Proven to Double Your Fat Burn, Says Study

Scientists reveal why you should consider working out on an empty stomach.

If you've never heard of the workout trend "fasted cardio," know that it isn't exactly rocket science. Put simply, it refers to exercising on an empty stomach, which usually means getting in your sweat session before you eat your breakfast. (So, if you've ever bounded out of bed in at 7am and went "running on empty" or did a spin class before grabbing your morning oatmeal, congrats! You've performed fasted cardio.) Many fitness enthusiasts swear by the practice, including the eternally ageless J.Lo.

Though past studies seem divided on the benefits of performing cardio in a fasted state, a study published last year in the Journal of Clinical Endocrinology & Metabolism found that participants who performed cardio before eating their first meal of the day actually experienced double the fat burn compared to those who exercised with food in their belly. "Rates of whole-body lipid utilization"—ie. "fat burn"—"were around 2-fold higher with exercise before versus after carbohydrate provision, and this difference between the conditions was sustained throughout the whole 6-week intervention," observes the study.

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The research, conducted at the University of Bath in the UK, focused on a group of sedentary but healthy men and divided them into two groups. One lived normally, while the other worked out in the mornings using stationary bikes and wearing fitness trackers. Those who exercised were either given shake before their ride or simply water that was disguised as a shake (in other words, it was a placebo). At the end of the six-week study, as mentioned, those who didn't have the shake ("breakfast") burned away double the calories.

The researchers say that the enhanced fat burn is because the fasted state forces the our bodies to burn stored energy in their muscles and fat.

Now, if you're sold on fasted cardio—and you're already setting your alarm clock for tomorrow—please know that there are some caveats here. Remember that "fat burn" doesn't necessarily translate directly into "weight loss," and when your body shifts to alternative fuel sources when no others are available, it may not always turn to just your fat. "Research shows that there's an increase in muscle breakdown when we exercise fasted, so it could actually decrease our strength," Meghann Featherstun, R.D., a specialist in sports dietetics, explained to Runner's World.

So if you're someone who is looking to build muscle, it's better to train with some fresh energy stores waiting in your belly. (After all, it's fasted "cardio" we're talking about here—not "fasted weightlifting.")

Our advice is to give it a go and see if you like how it feels. However, if you train super hard, you'd be wise fuel up. "In a fasted state, the physiology doesn't typically have the optimal resources for this type of [hardcore] exercise," David Chesworth, a personal trainer, explained to Healthline.

And whether or not you work out before breakfast or after breakfast, make sure you're eating the right breakfast. What follow are four amazing breakfast ideas you can use to power your own exercise and weight loss. So read on, and if you prefer to walk your way to better health in the AM, make sure you're of What Walking for Just 20 Minutes Does to Your Body, According to Science.

Flaxseed Buttermilk Pancakes

Waterbury Publications, Inc.

With these ingredients, you can enjoy this healthy twist on your favorite childhood breakfast guilt-free.

Get our recipe for Flaxseed Buttermilk Pancakes.

Black Bean Omelet

Black bean omelet
Mitch Mandel and Thomas MacDonald

This veggie omelet has it all: protein, vegetables, and, yes, beans. If beans are good enough for the world's oldest people, they're good enough for you.

Get our recipe for Black Bean Omelet.

Waffle With Ham and Egg

Healthy waffles with ham and egg
Mitch Mandel and Thomas MacDonald

Believe it or not, the portion-perfect (and, yes, healthy) combination is an excellent way to start the day.

Get our recipe for Waffle With Ham and Egg.

Raspberry-Peach Swirled Smoothie

raspberry peach swirled smoothies
Waterbury Publications, Inc.

Love a smoothie? Trying this delicious morning boost that contains frozen raspberries, peaches, a banana, orange juice, and Greek yogurt—along with some honey and ginger, too. Throw it in the blender and presto, you're ready to start your day.

Get our recipe for Raspberry-Peach Swirled Smoothie.

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William Mayle
William Mayle is a UK-based writer who specializes in science, health, fitness, and other lifestyle topics. Read more about William