Can I build muscle if I eat once a day? The Truth About OMAD and Gains

October 13, 2025 •

4 min read

While some studies show that intermittent fasting can increase fat loss and improve insulin sensitivity, research suggests that eating your entire day's calories and protein in one sitting may not be the most optimal strategy for maximizing muscle growth. Understanding the body's anabolic processes is crucial when asking, "Can I build muscle if I eat once a day?".

Quick Summary

This article examines the feasibility of building muscle while following a one-meal-a-day (OMAD) diet. It covers the nutritional challenges, including difficulty meeting protein targets and achieving a caloric surplus, and contrasts it with traditional meal frequency models. The discussion also includes potential benefits related to fat loss and offers strategies for optimizing an OMAD approach for strength training goals.

Key Points

Muscle Protein Synthesis is Less Optimized: Consuming all protein in one meal limits the number of times muscle protein synthesis (MPS) is stimulated throughout the day, which is generally not ideal for maximum muscle growth.
Meeting Caloric and Protein Demands is Challenging: It can be very difficult to consume the high volume of calories and protein needed for muscle growth in a single meal without feeling bloated or overly full.
Strategic Meal Timing is Crucial: To maximize benefits, it is best to time your one meal shortly after your resistance training session to fuel recovery and muscle repair.
Nutrient Density is Key: If following OMAD, the single meal must be extremely nutrient-dense, containing ample high-quality protein, complex carbohydrates, and healthy fats, along with a wide range of micronutrients.
Potential for Muscle Preservation, Not Optimal Growth: While OMAD can be effective for fat loss and may help preserve muscle mass, it is not the most efficient method for rapid or maximized muscle gain.
Hydration and Quality Fuel Matter: Staying well-hydrated during the long fasting window and consuming a well-balanced, whole-foods meal are critical for sustaining energy and promoting overall health.

Understanding Muscle Growth and OMAD

Building muscle, or hypertrophy, depends on a few key factors: providing a consistent stimulus through resistance training, consuming sufficient calories (often a surplus), and adequate protein intake to facilitate muscle repair and synthesis. One-Meal-A-Day (OMAD) is an extreme form of intermittent fasting where all daily nutritional intake occurs within a single, condensed eating window, typically 1 to 2 hours. This approach presents a unique set of challenges and considerations for those with muscle-building goals.

The Challenge of Muscle Protein Synthesis

Muscle protein synthesis (MPS) is the process by which the body builds new muscle proteins. For optimal muscle growth, it is generally recommended to keep MPS elevated by distributing protein intake throughout the day. Scientific research indicates that a single meal containing 20-40 grams of high-quality protein can maximally stimulate MPS in healthy adults. While a recent study did show that the body can utilize up to 100 grams of protein in one sitting for tissue-building, this is not a common or necessarily superior method. By consuming protein only once, you miss multiple opportunities to stimulate MPS, which may result in less overall muscle growth over time compared to a more traditional, evenly spaced meal pattern.

The Calorie and Nutrient Hurdle

To gain muscle mass, most individuals need to be in a caloric surplus, meaning they consume more calories than they burn. For many, consuming a caloric surplus—along with the very high protein requirements for muscle growth (1.6-2.2 g/kg of body weight)—is extremely difficult to achieve in a single meal without feeling uncomfortably full. The volume of food required to meet these needs, particularly nutrient-dense, whole foods, can be immense. Furthermore, restrictive diets like OMAD can make it difficult to get all the necessary vitamins, minerals, and fiber, potentially leading to deficiencies. Planning and preparation are crucial to ensure the single meal is packed with the correct balance of macronutrients and micronutrients.

Pros and Cons of OMAD for Muscle Building


Feature	OMAD (One Meal a Day)	Traditional Multiple-Meal Diet
Muscle Protein Synthesis	Stimulated only once per day, potentially suboptimal for maximizing growth.	Stimulated multiple times, providing sustained anabolic signals throughout the day.
Meeting Calorie Needs	Challenging to consume large caloric surplus in one meal; potential for bloating and indigestion.	Easier to achieve a controlled caloric surplus by spreading meals out, reducing feelings of excessive fullness.
Protein Intake	Can be very hard to ingest 1.6-2.2 g/kg body weight in one meal.	Daily protein can be distributed easily across 3-6 meals or snacks, ensuring steady supply.
Workout Performance	Potential for reduced energy during fasted workouts, though some report stable energy.	Consistent energy supply from regular meals can support intense training sessions.
Fat Loss	Highly effective for promoting fat loss by extending fasting windows and naturally restricting calories.	Can also achieve fat loss through consistent caloric deficit, but may not have the same hormonal benefits of prolonged fasting.
Growth Hormone	Increases human growth hormone (HGH) levels during fasting, which can help preserve muscle during weight loss.	HGH is not elevated in the same way, as fasting periods are shorter.

Strategies for Optimizing OMAD for Muscle Gain

If you choose to pursue OMAD despite the potential downsides for maximizing muscle growth, here are some strategies to help mitigate the risks and improve your results:

Time Your Meal Strategically: Schedule your one meal for shortly after your resistance training session. This allows your body to immediately use the incoming nutrients for recovery and muscle repair, capitalizing on the post-workout anabolic window.
Prioritize Protein: Make sure your single meal is rich in high-quality protein sources. Focus on lean meats, poultry, fish, eggs, dairy, or plant-based proteins like soy and legumes. Utilize protein supplements if necessary to meet high daily targets, perhaps mixing a shake with your meal.
Pack in Nutrient-Dense Calories: Include complex carbohydrates (quinoa, sweet potatoes) and healthy fats (avocado, nuts, olive oil) to provide the necessary calories for energy and growth without relying on junk food.
Stay Hydrated: Drink plenty of water throughout the fasting period. This helps manage hunger and supports overall bodily functions critical for exercise and recovery.
Ease In: Transitioning gradually from a regular eating pattern to OMAD can help your body adapt and minimize side effects like fatigue or intense hunger.

Is OMAD Right for You?

Ultimately, building muscle on OMAD is possible, but it is not the most efficient method for maximizing hypertrophy. While it offers benefits like increased fat oxidation and convenience, it requires meticulous planning to ensure adequate protein, calories, and micronutrients are consumed in a single, large meal. For dedicated bodybuilders or athletes aiming for peak muscle growth, a more frequent meal pattern is generally recommended to optimize muscle protein synthesis. For individuals prioritizing convenience or fat loss while maintaining muscle, OMAD can be a viable, though challenging, option.

A small 2022 study showed that participants eating one meal a day experienced significant decreases in body fat while maintaining lean mass, but this was a short-term trial with lean, healthy subjects and may not reflect long-term outcomes for all individuals. To effectively balance muscle maintenance and fat loss, OMAD requires careful attention to the nutritional quality of the single meal. Before adopting any extreme eating pattern, consulting a healthcare provider or a registered dietitian is always recommended, especially if you have pre-existing health conditions like diabetes.

For more detailed research on the effects of different eating patterns on metabolism and body composition, consider exploring studies indexed on the NIH's PubMed Central. [https://pmc.ncbi.nlm.nih.gov/articles/PMC8787212/].

Frequently Asked Questions

Yes, it is possible to gain muscle while eating once a day, but it is not optimal for maximizing muscle hypertrophy. Your success depends heavily on consistently consuming enough total calories and high-quality protein within that single meal, combined with effective resistance training.

OMAD is not ideal because it provides only one window for stimulating muscle protein synthesis (MPS), whereas distributing protein intake across multiple meals generally leads to more frequent and sustained MPS signals. It is also difficult to consume the necessary caloric surplus and high protein intake in a single meal.

It is technically possible to consume your daily protein requirements in one meal, but it is challenging. For serious lifters, the amount of protein needed (1.6-2.2 g/kg of body weight) can be difficult to eat in one sitting. Some research shows the body can utilize up to 100 grams of protein in one meal, but a more frequent intake is often better.

You can potentially lose muscle mass on an OMAD diet, especially if you do not consume enough protein or calories overall and do not engage in resistance training. However, with sufficient training and a well-planned, high-protein meal, research suggests you can preserve lean mass while losing fat.

Exercising in a fasted state on OMAD is a matter of personal preference and may not be more effective for muscle building. Some find their performance decreases, while others feel fine. If you do train fasted, it's recommended to consume your single, high-protein meal shortly after.

Yes, for many people, it is very difficult to achieve the caloric surplus needed for muscle growth by eating just one meal. This can result in feeling excessively full, and it requires strategic planning to ensure the meal is sufficiently calorie-dense without relying on unhealthy foods.

No, evidence suggests that OMAD is not superior to eating multiple meals a day for muscle gain. Spreading protein and calories over several meals is a more effective strategy for maximizing muscle protein synthesis and overall growth.