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What Is a Fasted Workout?

Here's Why a Trainer and a Nutritionist Both Say to Skip Breakfast Before a Morning Workout

Photographer: Diggy LloydRestrictions: Editorial and internal use only. No advertising or print.Product Credits: Nike top and pants, APL sneakers.

Do you head to the gym before breakfast? While some prefer eating before a workout to prevent nausea, others utilize exercising on an empty stomach as a way to reach weight-loss goals. As it turns out, a fasted workout (working out on an empty stomach) has some serious advantages, scientifically speaking. "I personally love fasted workouts," said Precision Nutrition coach and personal trainer Austin Lopez, CSCS. "They feel hard at first, but your body gets used to it and soon you prefer it." Let's get into those benefits.

It's an Easier Way to "Fast"

Ever wonder why the first meal of the day is called "breakfast"? Has the light bulb turned on yet? OK, great. You've been fasting this whole time . . . you're just sleeping through it! "I suggest working out first thing in the morning when you've already naturally 'fasted' while you sleep," said clinical nutritionist Autumn Bates, CCN, CPT. She explained that you can reap the benefits of fasting without getting into full-blown intermittent fasting (IF) by trying a morning workout on an empty stomach.

It's a Surefire Way to Burn Fat

One of those benefits? Weight loss! "Studies show that growth hormone levels increase after a period of intermittent fasting," said Bates. Why is this important? "Increased growth hormone levels cause your body to gain muscle while simultaneously burning fat. You can take advantage of this raise in growth hormone by working out on an empty stomach, first thing in the morning."

"The idea is that you manipulate your body to prioritize fat as a source of energy, because it doesn't have carbohydrates to use as a source, as those were digested and stored hours ago," said Lopez. However, while this is great for fat burning, there's a catch.

"If you go too hard on your body with no stored energy, then you risk utilizing amino acids as energy — aka burning muscle," he told POPSUGAR. To prevent this, you can rely on a supplement (if you need it). "This is why I personally start with a BCAA [branched chain amino acid] supplement that doesn't take me out of my fast," he said. "If anything, the BCAAs add protein to the mix so my body doesn't end up using muscle as fuel. I have found it to be effective for all types of workouts."

You Might Feel More Energized

You won't just burn fat, but you'll supercharge your morning, too. "A bonus factor to working out in a fasted state: you can increase your testosterone levels," said Bates. "This is a good thing because testosterone helps to reduce body fat and increase energy levels!"

Make Sure You Nourish and Hydrate Appropriately

"When it comes to breaking your fast post-workout, eat whenever you feel hungry, whether it be immediately after your workout or hours later," Bates told POPSUGAR. "However, it's especially important to hydrate both during and immediately after your workout in order to prevent dehydration and muscle fatigue," she said. "You lose a lot of water while you sleep, so hydration is key for performance."

In addition, you'll want to fuel up with the right nutrients after your workout. Post-workout nutrition is especially important when you're doing fasted workouts. "For your 'break fast' meal post-workout, I recommend having a smoothie with healthy fats, proteins, and carbs," said Bates. "The fiber and healthy fats will help to slowly absorb the carbohydrates so that your body doesn't have a spike and fall in glucose levels. Plus, the protein will help to repair your muscles and decrease DOMS [delayed-onset muscle soreness]."

And make sure you're eating enough. "Some people — I typically see this in women — drop too low in calories and end up stopping all fat loss," said Lopez. He noted that if you're doing a fasted workout in addition to IF during the rest of the day, you might be too calorie deficient — and that could cause your weight-loss plan to backfire. "Eating only a few hundred calories in total could stop all your progress," he said. "Focus on micronutrients and make sure you are only trying to lose a sustainable amount of weight per week. The recommended amount is 250-500 less calories per day to lose about one pound per week."

Image Source: POPSUGAR Photography / Diggy Lloyd
Product Credit: Nike top and pants, APL sneakers
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