What to Know: Intermittent Fasting and Working Out

Whether you choose intermittent fasting long-term or participate for a little while with a specific goal in mind, there are several reasons to begin a fasting program. Reasons such as losing weight, boosting immunity, reducing inflammation, improving cellular repair and brain function. Each is a valid reason, however, no matter the motivation, lots of folks choose to exercise while on an eating plan, which leaves many to wonder about the correlation between intermittent fasting and working out.

Of course, regular exercise is a way to keep our bodies healthy and agile while burning calories, and there are a plethora of ways to move our bodies. Many people choose to head outdoors on a hike, others join fitness classes online or at a local facility, and others decide to lift weights and do cardio. All of this begs the question of whether or not you can exercise while you are intermittent fasting.

Can I exercise while intermittent fasting? 

In short, YES!!  We’ll need to clarify a bit. For example during a regular daily fasting plan, such as 20/4 intermittent fasting, you have periods of going without food (fasting) and times where you can eat (consumption). When you are on a daily regimen, you can work out as you wish, although you may want to avoid times towards the very end of a fasting period.

In fact, some experts suggest that you exercise immediately after eating before your body has time to digest and absorb the food. Although, that would depend on what you ate and how much you’ve consumed, of course. It may not be the best idea to hit the gym after a few slices of cheesy pizza or a big steak.

Another caveat is for those who are doing multi-day fasts as opposed to a 16/8 plan. If you are fasting for multiple days on end, you may end up feeling dizzy or lethargic due to low blood sugar. If you have diabetes or high blood pressure, working out may not be in your best interest when you are fasting on a multi-day plan.

Of course, the nuance comes down to the type of exercise you’re doing, as there is a big difference between taking a brisk walk and going for a trail run. Whether you’re strength training with large amounts of weight or at home doing yoga, it also makes a difference. Don’t just think about exercise as a whole, but consider the specific type of activity you want to include during intermittent fasting.

Our advice, consult with your doctor about the perfect exercise and fasting plan combination for you. Doing so will set you up for success both with fasting and if (and when) to include movement while you are on an eating plan.

Where does energy come from while intermittent fasting? 

Our bodies can do amazing things and take care of themselves. Your body relies on its storage systems when exercising during an intermittent fasting plan. Fat reserves provide the necessary glucose to your cells to power any exercise activities.

Insulin from the pancreas helps move essential sugars to where they need to go, but your body gets reserves from the stored fat while you are fasting, so exercising while fasting is a fabulous way to help banish excess stored fat.

How is my athletic performance affected while intermittent fasting?

Again, this depends on your fasting plan. A lighter schedule, such as 16/8 intermittent fasting, is easy to combine with working out. However, other methods, such as OMAD and multi-day fasting, may be more difficult for those who count on their athletic performance for competitions or their vocation.

A study was conducted in 2009 during Ramadan, a month-long fast from sunrise to sunset in Islamic practice, which involved testing practicing Muslim athletes and their athletic performance. The results stated that the fast “imposes a major challenge to Islamic athletes.” They experienced fatigue; however, the effects were lessened with those who were conscious about getting enough sleep and eating healthy foods.

Another study confirmed the fact that proper sleep habits and nutrient intake—both hydration and caloric—aided in better performance. In short, if you are a competitive athlete who's practicing intermittent fasting, you need to concentrate on the basics of quality sleep, staying hydrated, and being conscious about when and where your calories come from.

How to Safely Exercise While Intermittent Fasting

Again, consult a doctor about both your fasting and exercise plan, especially if you decide to combine the two. Your doctor will know your health history and any ailments, such as high cholesterol or a history of heart disease, that can help you shape the perfect plan. Beyond that, there are several things that you need to consider when exercising during your intermittent fasting plan.

Stay hydrated.

Water and nutrients fuel our bodies, so being properly hydrated while you are sweating is vital. Take a water bottle along on hikes, to your cycling class, or to hit the machines at your local gym. Replenishing your water supply is essential to help your body function at its best, especially while you're fasting.

Don't Skip out before athletic competitions.

If you are a hard-core athlete or participate in athletic competitions—bodybuilding, marathons, and the like—you need to be at your peak. Not that fasting is harmful to you, but giving your body all of the nutrients it needs to burn calories effectively will allow you to perform better. The amount of calories you will burn while competing needs to be readily available, and you don’t want to risk feeling lightheaded or nauseous due to lack of food.

Eat right.

Working out requires carbs and dense calories. If you make a meal simply based on calories, you could consume 1500 calories of gummy worms and candy bars (not advisable, no matter the circumstance). However, the wiser choice is to feast on a nutrient-dense meal of vegetables and quality meats. Make those calories and meals count! Of course, you can have a few sweets, but make that a treat and not a meal substitute.

Time your fasting right.

Again, some experts say to load up on calories before you work out and then start your fast. Others claim that using your body’s natural rhythms is ideal, which would involve exercising first thing in the morning. For most people, a morning workout is what fits best into their schedule anyway, so get it out of the way as your first activity of the day. It will help you wake up, and you can sneak in that workout before the hunger pangs hit.

Consider a mini-meal.

If you’re feeling a bit “off” before, during, or after exercise, you may want to schedule your intermittent fasting time so that you can have a mini-meal right before your workout if a full meal isn’t on the docket. Hint: our bars are a great way to fuel up pre-workout so that you can consume necessary calories and feel good about what you’re putting into your body

Another great mini-meal option is to include a healthy smoothie into your routine. On a 16/8 intermittent fasting plan, you should be able to coordinate your fasting and consumption times incredibly easily so that you can have a snack before you hit the gym.

Listen to your body’s signals.

Perhaps there’s no better sign than when your body lets you know that something isn’t right. Feeling lightheaded, having issues with coordination, and experiencing blurred vision are all ways that your body tries to get your attention.

If you experience any of these things during a workout, you most likely need to stop exercising immediately. Consult your doctor so that you can adjust your exercise and fasting plan accordingly. Burning fat is a good thing, but when you’re sacrificing your health—say, if you pass out while holding heavy weights or during a run—it's not worth it.

Did we mention you should talk to your doctor? 

We did, right (maybe only a few times)?  Please make a note of it, especially if you have any underlying health issues. It may be a reason for you to schedule that annual physical you’ve been putting off anyway. We can give you all the well-researched advice we can (and we’ve got lots!), but consulting a pro who can customize a plan is highly beneficial to your overall health.

Are you ready to start working out while intermittent fasting? 

If your goal is to have a healthy lifestyle, give it a go! Consider both your exercise and intermittent fasting plans, chat with your doctor (last time, we promise!), and be very conscious about how you take care of yourself. Getting enough sleep, consuming healthy nutrients, and drinking water are essential, as is listening to your body. After all, your body's signals give you the best indicator of what is ideal for you.

Whether you plan a daily morning walk with your dog or BFF, explore the great outdoors with your partner, jump into the next pick up hoops game or find a new friend to pump iron with at the gym, combining intermittent fasting with working out can be safe, fun, and beneficial to your health.