Building Muscle with Intermittent Fasting: What You Need to Know

One of the most common questions in the fitness world is whether you can combine intermittent fasting with strength training to gain muscle.

This topic has generated confusion around fasting muscle loss myths, so we intend to bring some clarity.

Keep reading to understand how to integrate intermittent fasting into your training plans effectively.

Can You Gain Muscle While Intermittent Fasting?

To address this question, we must first understand intermittent fasting (1). 

Simply put, it is an eating pattern that alternates between fasting and eating periods. 

This approach focuses more on when than what to eat (2).

Gaining muscle mass involves combining adequate resistance training with a caloric intake that supports muscle growth (3). You must consume sufficient protein and maintain a positive energy balance to build muscle. 

Aim for a balanced diet that includes:

• Fruits
• Vegetables
• Healthy fats
• Whole grains
• Animal or plant protein (4) (5)

Although intermittent fasting might seem contradictory to this goal, many individuals have successfully combined it with an appropriate muscle-building training regimen.

It is essential to recognize that everyone is different, but generally speaking, it is possible to gain muscle mass while practicing intermittent fasting!

The 3 primary keys lie in:

1. Adapting your lifestyle with proper planning
2. Finding the type of fasting that best suits you
3. Ensuring high-quality nutrients in your diet

Additionally, intermittent fasting exercise is feasible and effective. 

Many successfully incorporate workouts into their fasting schedule, often timing their exercise sessions to align with their eating windows to optimize energy levels and recovery.

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What is the Best Approach to Intermittent Fasting Muscle Gain?

Gaining muscle mass while intermittent fasting might seem impossible, but it is achievable with the right approach.

This process requires strategic meal planning, a well-structured training plan, and lifestyle adjustments to maximize results. 

Here’s how to gain muscle mass through intermittent fasting:

• Choose the type of fasting that fits you: 

Several intermittent fasting methods exist, but the 16/8 fasting muscle gain method is worth trying. This method involves 16 hours of fasting and 8 hours of eating.

Many bodybuilders consider this method the best intermittent fasting for gaining muscle.

The 16/8 approach allows a sufficiently wide daily eating window to consume the necessary nutrients for muscle growth or maintenance (6). 

Read more: 18:6 Intermittent Fasting: Can Eating Only 2 Full Meals Help You Slim Down?

• Plan your meals: 

Consume different combinations of nutrient-rich foods, such as lean proteins, complex carbohydrates, healthy fats, fruits, and vegetables (5). Dive deeper into the fasting meal plan for begginers with our dedicated article.

• Synchronize your workouts: 

It will help to schedule your resistance training sessions during or near eating windows. 

This strategy can help maximize energy during exercise and improve muscle recovery after training (7).

• Listen to your body: 

Pay attention to how you feel during fasting and training. 

If you have extreme fatigue or low energy, use it as a sign to adjust the approach or consult a healthcare professional and registered dietitian.

• Hydration and rest: 

Staying well-hydrated and ensuring sufficient sleep is crucial for recovery and muscle growth (8).

By following these guidelines, you will gain muscle mass while intermittent fasting and adequately meet your nutritional and physical needs.

Will I Lose Muscle If I Workout While Fasting?

There are several myths about muscle loss related to fasting. This idea can cause concern among those considering exercising while fasting, fearing they might lose muscle. 

However, experts do not guarantee that muscle mass loss happens when training in a fasted state.

You can minimize the risk with proper planning and a good understanding of how the body manages its energy reserves.

Factors such as the fast’s duration and frequency, the exercise’s type and intensity, and overall nutritional intake are essential factors in determining the impact of fasting exercise on muscle mass.

 To ensure exercising while fasting does not compromise muscle mass, researchers recommend:

• Adequate protein intake
• Amino acid supplementation
• Effective post-workout recovery (9)

Read more: Static Stretching: The Ultimate Post-Workout Routine

Does Fasting Increase Testosterone?

First, let’s talk a bit about testosterone. 

This hormone is vital for the development of:

• Bone density
• Overall well-being
• Male sexual characteristics
• The maintenance of muscle mass

Primarily produced in the male testes, testosterone is also present in smaller amounts in women (10).

Some studies (11) (12) (13) suggest that fasting, especially when combined with exercise, might reduce testosterone levels.

However, this reduction does not negatively affect strength or muscle mass, which is good news for those concerned about maintaining their physical performance.

On the other hand, research also highlights how fasting may improve insulin sensitivity and contribute to weight loss (14) (15). These changes can positively impact overall hormonal balance, including testosterone production.

While fasting could have mixed effects on testosterone levels, the potential benefits for insulin sensitivity and weight loss contribute to a healthier hormonal balance without affecting muscle mass or exercise performance. 

As always, it is essential to consider how fasting fits your needs and consult a healthcare professional before significantly changing your diet or exercise routine.

Do Bodybuilders Do Intermittent Fasting?

Some bodybuilders incorporate intermittent fasting into their training and nutrition regimen, leveraging its potential benefits to reduce body fat percentage while maintaining muscle mass (16).

Intermittent fasting in bodybuilders might also increase levels of human growth hormone (HGH), aiding muscle preservation and enhancing metabolism (17). 

Additionally, intermittent fasting promotes autophagy, a cellular process that recycles damaged components, thereby improving cellular health and muscle recovery (18).

Some bodybuilders ask how to slow down your metabolism with fasting to prevent muscle loss. 

However, you don’t need to worry about this issue if you reach the same calories and protein amounts as you were consuming before, but now, within your eating window.

Pro tips:

• Ensure your diet plan meets your goals and is solid.
• Aim to reach the same calorie and macronutrient totals as before.
• Avoid undereating during the feeding window to maintain gym performance and muscle goals (19).

However, the effectiveness and suitability of intermittent fasting can vary depending on the individual, their specific goals, and their body’s response to fasting. 

Bodybuilders who wish to use intermittent fasting as part of their muscle development regimen must do so in an informed manner.

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Does 48 Hour Fast Burn Muscle?

A 48-hour fast can raise concerns about muscle loss, but a single 48-hour fast does not necessarily result in significant muscle burning if appropriately managed. 

During a prolonged fast, the body initially uses glycogen stores and then begins to burn fat for energy. 

However, muscle loss could occur if you frequently extend the fast too long or fast for long periods without adequate protein and nutrient intake during feeding periods.

To minimize muscle loss during a 48-hour fast, it is essential to:

• Ensure adequate protein intake before and after the fast to support muscle protein synthesis.
• Engage in regular resistance training, which helps preserve muscle mass.
• Stay adequately hydrated and consider electrolyte supplementation if necessary.

Many wonder, “Will I lose muscle if I fast for 5 days?”

The answer is yes because muscle atrophy is a significant risk during a 5-day fast. 

This breakdown of muscle tissue happens when you don’t eat. Your body begins to search for energy and starts using muscles for fuel. 

However, studies show that you can reach ketogenesis and prevent muscle loss with physical activity during a fast (20, 21).

Always consult a healthcare provider before trying prolonged fasts such as 5 to 10-day fasts to reduce risks and do what fits your body best.

Frequently Asked Questions

• Does intermittent fasting get you ripped?

Intermittent fasting can be an effective tool for some individuals seeking to improve body composition and define their figure by facilitating fat loss and maintaining muscle mass. 

It alternates periods of fasting with eating, which can reduce calorie intake and improve metabolism.

However, its effectiveness varies among individuals, and you should include a balanced diet with regular exercise to achieve the best results.

• Should gym goers do intermittent fasting?

Intermittent fasting is not a general rule for everyone who goes to the gym. 

Listening to your body and understanding that each person responds differently to this regimen is essential.

Some individuals may find intermittent fasting helps them lose fat and maintain muscle mass. In contrast, others may experience a decrease in performance or not feel well when training on an empty stomach.

For those who cannot or prefer not to fast, achieving effective results is possible through healthy habits and a well-structured training regimen.

Consider this: Some people enjoy working out at night while others prefer during the day. 

You do what fits your schedule, your body’s needs, and what aligns with your goals.

A balanced diet and an appropriate exercise program can be equally effective in improving body composition and reaching fitness goals.

• Does a 7 day fast burn muscle?

A 7-day fast does not necessarily result in significant muscle mass loss, although there is a possibility that it might occur. 

During a prolonged fast, the body might start using muscle proteins as an energy source in addition to glycogen and stored fat.

Reduce muscle loss by:

• Hydration
• Rest and recovery
• Consuming enough protein
• Resistance exercises in moderation

Always keep in mind not to overburden the body during a prolonged fast.

The Bottom Line

You can gain muscle while intermittent fasting with the right strategy. 

The main focus is to adapt fasting to your lifestyle, ensuring you fill your eating windows with essential nutrients such as proteins, complex carbohydrates, and healthy fats.

Additionally, scheduling workouts during these windows will maximize the energy available for intermittent fasting exercise and enhance post-workout muscle recovery.

Listen to your body and adjust the approach with a healthcare professional as needed.

With careful planning and personalized adjustments, you can use intermittent fasting as an effective tool to support muscle growth and improve body composition.