Skip to Content

What To Know About Intermittent Fasting When Working Out

Please share:

Intermittent fasting (IF) has gained significant popularity as a dieting strategy in recent years, promising benefits such as weight loss, improved metabolic health, and enhanced longevity. But how does this dietary pattern mesh with regular exercise routines? Here’s a comprehensive look at what you need to know about combining intermittent fasting with working out.

Know About Intermittent Fasting

Understanding Intermittent Fasting

Intermittent fasting isn’t about what you eat, but when you eat. The most common methods include:

  1. 16/8 Method: Fast for 16 hours and eat during an 8-hour window.
  2. 5:2 Diet: Eat normally for five days a week and reduce calorie intake to about 500-600 calories on two non-consecutive days.
  3. Eat-Stop-Eat: Incorporate 24-hour fasts once or twice a week.

Fasting periods can range from 12 hours to several days, but for most, the 16/8 method is the most sustainable and compatible with an active lifestyle.

Benefits of Intermittent Fasting When Working Out

Enhanced Fat Burning

During fasting, insulin levels drop significantly, facilitating fat burning. Exercise during a fasted state can amplify this effect, as the body is more likely to tap into fat stores for energy.

Improved Insulin Sensitivity

Both intermittent fasting and regular exercise improve insulin sensitivity. This means your body becomes more efficient at using glucose, which can be particularly beneficial for those with insulin resistance or type 2 diabetes.

Increased Human Growth Hormone (HGH) Production

Fasting and high-intensity exercise can increase levels of human growth hormone, which plays a vital role in muscle growth, fat metabolism, and overall recovery. Elevated HGH levels can help preserve lean muscle mass while losing fat.

Enhanced Muscle Recovery and Repair

Intermittent fasting can trigger cellular repair processes such as autophagy, where cells remove damaged components and regenerate new ones. Combined with exercise, this can lead to better recovery and muscle health.

Challenges and Considerations

Energy Levels

One of the primary concerns with exercising while fasting is energy levels. Initially, you might experience fatigue or reduced performance as your body adapts to utilizing fat as a primary energy source instead of glycogen. It’s crucial to listen to your body and adjust the intensity of your workouts accordingly.

Nutrient Timing

Timing your meals around your workouts is critical. For those on the 16/8 method, it’s often recommended to work out towards the end of the fasting period and break the fast with a nutrient-dense meal that includes protein and carbohydrates to aid recovery.


Staying hydrated is essential, especially during fasting periods. Dehydration can lead to decreased performance, fatigue, and dizziness. Drinking water, herbal teas, or electrolyte-infused beverages can help maintain hydration levels.

Muscle Loss Concerns

Some worry that intermittent fasting might lead to muscle loss. However, studies suggest that as long as protein intake is sufficient and resistance training is part of the regimen, muscle preservation is achievable. Combining intermittent fasting with a well-balanced diet rich in protein can help mitigate muscle loss.

Practical Tips for Intermittent Fasting and Exercise

Start Slow

If you’re new to intermittent fasting, ease into it. Begin with shorter fasting periods and gradually extend them as your body adapts. This gradual approach helps prevent overwhelming hunger and fatigue.

Choose the Right Type of Exercise

Not all workouts are created equal when it comes to fasting. Low-intensity exercises like walking, yoga, and light cardio are generally well-tolerated in a fasted state. High-intensity interval training (HIIT) and heavy lifting might be more challenging and could require some trial and error to find what works best for you.

Optimize Post-Workout Nutrition

Breaking your fast with a balanced meal is crucial. Aim for a mix of protein to aid muscle repair, carbohydrates to replenish glycogen stores, and healthy fats for sustained energy. Examples include a chicken and quinoa salad, a smoothie with a creatine supplement or protein powder, fruits, and nuts, or a lean meat and vegetable stir-fry.

Listen to Your Body

Your body will give you signals if something isn’t working. Pay attention to signs of overtraining, excessive fatigue, dizziness, or prolonged soreness. Adjust your fasting and workout routines as needed to maintain overall health and performance.

Consult a Professional

Before making significant changes to your diet and exercise routine, consult with a healthcare provider or a nutritionist. They can provide personalized advice based on your health status, fitness goals, and lifestyle.

There You Have It

Intermittent fasting and working out can be a powerful combination for those looking to optimize their health, lose weight, and improve metabolic function. While there are numerous benefits, it’s essential to approach this regimen mindfully. Proper meal timing, hydration, and listening to your body are key to successfully integrating intermittent fasting with your fitness routine. With the right approach, you can harness the benefits of both fasting and exercise to achieve your health and fitness goals.

Please share: