Can you still build muscle on OMAD? The science of One Meal a Day

October 12, 2025 •

4 min read

Research indicates that while one meal a day (OMAD) is effective for weight loss, it is often associated with challenges for maintaining or building lean muscle mass, especially without careful planning. But is it truly impossible? This article explores whether can you still build muscle on OMAD and what strategies are needed to make it work.

Quick Summary

Building muscle on an OMAD diet is possible but presents significant challenges due to difficulty meeting high protein and caloric requirements in one sitting. Success depends on consuming nutrient-dense food and combining the diet with consistent resistance training.

Key Points

Protein Intake is Critical: It is extremely challenging to consume the necessary amount of protein for muscle growth in just one meal, hindering optimal hypertrophy.
Timing Affects Synthesis: Spreading protein intake over multiple meals is superior for stimulating muscle protein synthesis throughout the day, a key driver for muscle growth.
Fat Loss is More Likely: OMAD is a highly effective strategy for fat loss, but this often comes with a significant challenge to simultaneously build or even maintain muscle mass.
Resistance Training is Vital: Performing regular resistance training is essential on OMAD to send the necessary signal for muscle preservation and growth.
Hormone Boost, Synthesis Missed: While OMAD can increase Human Growth Hormone, which aids muscle repair, the limited windows for muscle protein synthesis make it suboptimal for maximizing hypertrophy.
Meal Quality is Paramount: The single meal must be a nutrient-dense powerhouse to compensate for the limited eating window and prevent deficiencies that could hinder progress.
Long-term OMAD is Inefficient: For serious or long-term muscle-building goals, distributing protein and calories across multiple meals is a more evidence-based and effective approach.

The Core Principles of Muscle Growth

To understand the viability of building muscle on any diet, including One Meal a Day (OMAD), it's crucial to first grasp the fundamental physiological requirements for hypertrophy. Muscle growth, or hypertrophy, relies on three primary factors:

A Caloric Surplus: Consuming more calories than your body burns is generally considered optimal for gaining muscle mass. This extra energy fuels the muscle-building process and aids in recovery after resistance training.
Adequate Protein Intake: Protein is the building block of muscle. For muscle repair and growth, a high protein intake is essential. Experts recommend around 0.8 to 1 gram of protein per pound of body weight for those aiming to build muscle.
Consistent Resistance Training: A sufficient training stimulus is necessary to signal to the body that it needs to repair and build new muscle tissue stronger than before.

The OMAD Challenge for Hypertrophy

OMAD, by its nature, introduces several obstacles to meeting the conditions required for optimal muscle building. It restricts all caloric intake into a short, typically one- to two-hour window, followed by a prolonged 22-23 hour fast.

Caloric and Protein Demands

For many, consuming a caloric surplus in a single meal is challenging. It requires eating a very large volume of food in a short period, which can be uncomfortable and difficult to sustain. More critically, meeting the daily protein requirements for muscle gain can be nearly impossible in one sitting. For example, a 180-pound person might need 144 to 180 grams of protein, a massive amount to consume all at once.

The Role of Muscle Protein Synthesis

Muscle protein synthesis (MPS) is the process by which muscle protein is produced. Studies show that MPS is most effectively stimulated when protein is consumed regularly throughout the day in smaller doses (e.g., 20-55 grams). OMAD provides only one such opportunity, potentially missing out on multiple daily spikes in MPS that could contribute to greater overall muscle growth over time.

Strategies to Maximize Muscle Growth on OMAD

While OMAD is not the most efficient path to maximizing muscle hypertrophy, it's not entirely counterproductive, especially for those who prioritize fat loss while attempting to preserve muscle. Here are some strategies for those who insist on trying to build muscle on OMAD:

Prioritize Nutrient-Dense Foods: Your single meal must be a powerhouse of nutrition. Focus on high-quality, lean protein sources (e.g., steak, chicken, fish) and nutrient-rich carbohydrates and fats.
Optimize Protein Consumption: Some OMAD practitioners choose to 'stack' their protein intake by consuming a large, concentrated protein source, like a protein shake, alongside their main meal to ensure they hit their daily target.
Strategic Workout Timing: The timing of your workout can be adjusted to coincide with your one meal. For instance, lifting weights shortly before or after your meal can ensure you have readily available nutrients to fuel your workout and recover afterward.
Incorporate Resistance Training: Regardless of your eating pattern, resistance training is non-negotiable for preserving and building muscle mass. This is especially true on an OMAD diet to signal the body to hold onto lean mass during fasting periods.

Comparing OMAD and Traditional Eating for Muscle

To illustrate the differences, here is a comparison between OMAD and a traditional three-meal-a-day approach for building muscle.


Feature	OMAD (One Meal a Day)	Traditional Eating (3+ Meals)
Calorie Surplus	Possible, but challenging to consume enough calories in one meal.	Easier to achieve by distributing calories throughout the day.
Protein Distribution	All protein is consumed at once, leading to fewer spikes in muscle protein synthesis.	Protein can be distributed across meals, maximizing MPS stimulation.
Muscle Protein Synthesis	Stimulated less frequently, potentially limiting overall muscle growth over time.	Stimulated multiple times daily, which is more effective for building muscle.
Nutrient Absorption	A large single meal can tax the digestive system and may impact the body's ability to efficiently absorb all nutrients.	Smaller, regular meals are easier to digest, potentially leading to better nutrient absorption.
Hormone Balance	Can increase Human Growth Hormone (HGH) levels during fasting, which is beneficial for fat loss and muscle preservation.	Insulin levels remain relatively stable, but doesn't offer the fasting-induced HGH spikes.

Risks and Considerations for OMAD and Muscle Building

Beyond the primary challenges, several risks and considerations are associated with trying to build muscle on OMAD, including:

Nutrient Deficiencies: It is difficult to get all essential vitamins and minerals from just one meal, which can impair overall health and performance.
Fatigue and Low Energy: The extended fasting period can lead to low energy, especially during intense training sessions.
Increased Hunger and Bingeing: For some, the long fast can lead to extreme hunger, potentially causing poor food choices or binge eating during the eating window.
Metabolic Slowdown: While OMAD can boost metabolic flexibility in some cases, some concerns exist about potential metabolic slowdown with consistent and prolonged fasting.

Conclusion: The Bottom Line on OMAD and Muscle

Ultimately, while it is theoretically possible to build muscle on OMAD, it is not the most optimal or efficient method. The significant challenge lies in consistently meeting the caloric surplus and high protein intake necessary for hypertrophy within a single, brief eating window. For those with serious muscle-building goals, a more traditional eating pattern with regular protein feedings is scientifically proven to be more effective for maximizing muscle protein synthesis.

For those who prioritize fat loss and desire the simplicity of OMAD, it is a viable option that, when paired with strategic training and meal planning, can help preserve existing muscle mass while shedding fat. However, anyone considering this approach, especially for long-term muscle gain, should consult a healthcare provider or a registered dietitian to ensure their nutritional needs are met. For more insights into the metabolic effects of OMAD, you can review relevant research, such as this study on metabolic flexibility: Differential Effects of One Meal per Day in the Evening on Metabolic Health and Physical Performance in Lean Individuals.

Frequently Asked Questions

No, OMAD is not considered more effective for muscle growth. Spreading protein intake across multiple meals is better for consistently stimulating muscle protein synthesis, which is crucial for hypertrophy.

It is difficult to consume the high amount of protein required for muscle gain (around 0.8-1 gram per pound of body weight) in a single meal. Most research shows that the body best utilizes protein for muscle building when consumed in moderate amounts throughout the day.

There is a risk of losing muscle mass on an OMAD diet, especially without a consistent and focused resistance training program. Combining OMAD with regular weight training is key to minimizing this risk and encouraging muscle preservation.

Fasting periods, including those in OMAD, can increase Human Growth Hormone (HGH) levels, which helps with muscle preservation and fat burning. However, this HGH boost does not fully compensate for the limited opportunities to stimulate muscle protein synthesis through regular protein intake.

To optimize your OMAD meal for muscle building, focus on nutrient density. Include a significant amount of high-quality protein, complex carbohydrates, and healthy fats. Some people also add a concentrated protein supplement to help meet their needs.

OMAD is generally more effective for fat loss. The extended fasting period often leads to an automatic calorie deficit, and increased HGH levels aid in fat burning. It is significantly more challenging to build new muscle mass than to lose fat on this eating pattern.

For dedicated bodybuilders whose primary goal is to maximize muscle mass, OMAD is typically not recommended. The restrictive eating window and limited protein synthesis stimulation make it an inefficient strategy for achieving significant hypertrophy.