August 26, 2020
Last Updated:
April 28, 2021

Intermittent Fasting and Exercise – Know This Before Starting

What is intermittent fasting?

When done in a healthy and regulated way, intermittent fasting (IF) can be a great way to reset unhealthy eating habits. It’s been shown to combat insulin resistance, help steady blood sugar levels, create a calorie deficit that leads to weight loss, and promote a healthy metabolism. IF involves an elongated fasting period, coinciding with nighttime, followed by a shorter period when you eat your meals.

If you normally skip breakfast because you don’t seem to get hungry until lunchtime, IF can be easily integrated into your daily routine. You’ve already mastered the morning fasting part, so the next step would be to focus on avoiding any late-night snacking in order to set yourself up for success to continue fasting into the next day.

IF can become part of anyone’s routine, but as always, it’s important to seek out guidance and support from a nutrition expert who can help you figure out which eating pattern and fasting period works best for you.

Methods of intermittent fasting:

  • Overnight fasting

Fast for a twelve-hour period every day. This means eating dinner by 7pm and resuming meals with breakfast at 7am the next day.

  • 14:10 method

Fast for fourteen hours and eat meals in remaining ten hours. This could look like fasting from 7pm to 9am the following day.

  • 16:8 method

Fast for sixteen hours and eat meals in remaining eight hours. This could look like fasting from 8pm to 12pm the following day.

  • 5:2 method

Eat as you normally would five days of the week and limit your calorie intake to 500–600 calories for two days of the week. The two limited-calorie days should be spread out within the week.

  • One meal a day (OMAD) method

Eat one meal a day – the longest form of time-restricted eating.

 The 5:2 and OMAD methods are for more experienced fasters as they require elongated fasting periods. If you’re trying IF for the first time, it is not recommended to start with these methods. Instead, start with the overnight fasting as it is likely closest to your current routine.

 The benefits of intermittent fasting

IF focuses on revitalizing the body’s internal processes that keep you happy, satisfied, and energized by adhering to a consistent eating schedule. The major benefits of IF include:

  • Regulate blood sugar: When you eat a meal, blood sugar rises, causing the pancreas to release insulin to transport sugar out of the blood and into cells for energy. IF regulates blood sugar and insulin levels by allowing the pancreas to rest during the fasting state. This regulation helps prevent the development of type 2 diabetes and other lifestyle diseases caused by insulin resistance.
  • Reach a healthier weight: Fasting can help you reach a healthier weight for your body type by confining your meals to a specific eating period. This can help you avoid overeating and will most likely result in a calorie deficit.
  • Improve metabolism: IF can be used to kick-start your metabolism. When people lose weight, especially a lot of weight very quickly, they will often gain the weight back soon afterward, possibly because hunger hormones are triggered by the quick weight loss. IF is thought to prevent this plateau and weight regain from happening.

Exercising on an empty stomach

When done properly, IF can prepare your body to exercise in a fasted state by training it to properly tap into energy stores.

Food is required to energize and provide fuel to the body. When your diet is full of nutritious foods, it can further aid your stamina and help you perform at your best. Working out on an empty stomach is doable and safe if you’re preparing your body for a fasted workout. Many people may already be inadvertently fasting if they usually skip breakfast, but that doesn’t necessarily mean their body is physically prepared for an intense workout in a fasted state.

The goal is to figure out what works for your body in a fasted state. High-intensity cardio or weight training often require greater energy sources to pull from, which could look like saving your workout for the end of an eating window, when blood sugar levels are higher and your muscles can absorb sugar from the blood for energy. Don’t be scared to add a simple snack, like an apple or a handful of nuts, to kick-start an early morning workout if your body feels hungry. Try different methods to find the schedule that works best for your bio-individual needs.

Once your body adjusts to fasting, you can begin testing fasted-state workouts, including cardio, yoga, and cycling. Completing these exercises on an empty stomach will eventually train your body to begin tapping into your glycogen storage, burning fat as a result of your workout.

Types of exercises while fasting

There are plenty of ways to perform healthy physical activity while maintaining your fasting schedule:

  • Jogging
  • Yoga
  • Pilates
  • Cycling
  • Barre or flexibility training

These are all moderate to vigorous activities that are more easily performed on an empty stomach.

It’s important to build up to any intense exercise, taking little steps each day to run a bit faster or add in an extra pushup. Be sure to keep yourself properly hydrated, and be aware of any feelings of dizziness or fatigue that occur.

IF is often used as a weight loss tool, but you can build muscle as well by getting the proper macronutrients from your diet and incorporating weight training into your exercise routine. By saving your workout for about a half hour after you’ve eaten a nutritious meal, your body can perform better during high-intensity training. This is because the body will have a ready energy source rather than having to resort to breaking down muscle as source of fuel.

Vigorous weight training is best completed within your eating window of the day, ensuring you are properly prepared for your workout. It’s also ideal to recover with a protein- and carb-rich meal. Nitrate-rich foods, like leafy greens and citrus fruits, can help improve your oxygen intake and endurance in preparation for an intense weight-training session.

Whether you’re trying to lose weight, build muscle, or both, it’s important to learn to listen to your body and opt for physical activity that challenges you without completely draining you.

Eating right to get the most out of your workouts

Feed your body with whole foods, getting both micro- and macronutrients, to keep the body nourished before and after a workout. You may be eating fewer meals while engaging in IF, so it’s important that you get optimal nutritional value from what you put on your plate. The best way to do this is to plan your meals as best you can in relation to the workout or schedule you have for the day.

Here are some key tips to ensure you’re eating right:

  • Fuel your body with whole, unprocessed foods, like fish, vegetables, fruits, and healthy fats.
  • Eat carbohydrates on days you know you will be completing a difficult strength-training session. Carbs will help maintain your blood glucose level during your workout and replace muscle glycogen.
  • Help grow muscle mass and recover well by eating a mix of protein and carbs after your workout.
  • Drink ample amounts of water to stay hydrated throughout difficult physical activities.
  • Drink electrolytes, such as coconut water, or eat a banana to replenish what was lost during your workout.

A Health Coach can help you stick to your schedule, ensuring you listen to what your body needs and are able to amplify your workouts with a balanced, whole foods–based approach.

Do what feels right.

There’s no quick fix to eating right and creating a healthy life for yourself. You can, however, make small, impactful changes that bring this goal into fruition. Physical activity is an essential area of primary food that nourishes both the body and mind, but in order to integrate it healthily while IF, it has to be done in an intentional and guided way.

Be gentle with yourself and stay open to the possibility of reevaluating your routine, which can be done with the help of a dietitian or Health Coach, to find a fasting schedule that fits you and your needs. If you find yourself experiencing any brain fog, weakness, or obsessive thoughts about food, chances are you are not doing what’s best for your body.

The path to whole-body health should be a positive and illuminating experience that enhances all other areas of your life. Check out the IIN Curriculum Guide today to learn more about how an intentional and bio-individualized focus on your well-being can result in your healthiest, happiest self.


Author Biography
Rebecca Robin
IIN Content Writer

Rebecca holds a bachelor’s in English with a focus in public relations and has a writing background in retail and entertainment advertising. Some of her favorite things include juicing, creating the perfect bowl of oatmeal, and getting in a HIIT workout.

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