How Much Protein Is Needed for MPs? Decoding Requirements for Athletes

December 1, 2025 •

4 min read

For endurance athletes like marathon participants, daily protein needs are up to twice the minimum recommended dietary allowance. This guide deciphers how much protein is needed for MPs, addressing its importance for both endurance sports and general muscle synthesis.

Quick Summary

This article clarifies the term 'MPs' in a fitness context, outlining distinct protein requirements for endurance athletes like marathon runners versus active individuals focused on muscle protein synthesis and recovery.

Key Points

Endurance Athletes Need More Protein: Marathon participants and other endurance athletes require 1.4–1.8 g of protein per kilogram of body weight daily for muscle repair and recovery.
Strength Athletes Maximize MPS: For muscle growth via Muscle Protein Synthesis (MPS), a target of 1.6–2.2 g/kg/day is recommended.
Even Distribution is Key: Spreading protein intake across the day in 3–5 hour intervals, with 20–40g per meal, supports a consistent supply of amino acids.
Consider Pre-Sleep Protein: Consuming a slow-digesting protein like casein before bed can enhance overnight muscle protein synthesis.
Total Intake Trumps Timing: The overall daily protein intake is more important for muscular adaptations than the timing immediately around a workout.
Needs Increase During Caloric Restriction: Athletes in a calorie deficit need to consume more protein (2.0–2.5 g/kg/day) to prevent the loss of lean muscle mass.

Decoding the Term "MPs"

In the world of fitness and sports nutrition, the abbreviation "MPs" can be a source of confusion. While search results show it can mean 'Metabolizable Protein' in animal science, in a human context, it more likely refers to 'Marathon Participants' or is a typo for 'Muscle Protein Synthesis' (MPS). This article provides clarity on protein needs for both endurance athletes (like marathon participants) and for the fundamental process of MPS.

Protein for Endurance Athletes: Marathon Runners and Beyond

Endurance sports, such as long-distance running, place significant stress on the body, including muscle breakdown. Therefore, protein needs are elevated compared to the average, sedentary person. The International Society of Sports Nutrition recommends a daily protein intake of 1.4–2.0 g per kilogram of body weight for active individuals. For endurance athletes, recent research suggests aiming for the higher end of this range, or even up to 1.8 g/kg/day, is most appropriate.

During periods of intense, high-volume training, or if an athlete is in a caloric deficit (common during weight loss phases), protein requirements may increase further, potentially up to 2.0–2.5 g/kg/day, to preserve lean muscle mass and aid recovery. This increased intake is crucial for repairing muscle micro-tears and maintaining a robust immune system.

In-Race Protein for Ultramarathons

For extremely long endurance events like ultramarathons, consuming small amounts of protein during the race can be beneficial. Recommendations suggest consuming 5–10 grams of protein per hour, which can help curb hunger and mitigate muscle damage.

Protein for Muscle Protein Synthesis (MPS)

Muscle protein synthesis (MPS) is the natural process of rebuilding and repairing muscle fibers, which is stimulated by both exercise and protein consumption. For individuals aiming to build or maintain muscle mass through resistance training, maximizing MPS is a primary goal. Studies show that consuming a sufficient amount of protein after exercise enhances this process. The anabolic response to protein is dose-dependent but saturable, meaning there is a threshold beyond which more protein does not yield greater MPS benefits.

Optimal Per-Meal Intake

Research suggests that to maximize MPS, an intake of 20–40 grams of high-quality protein per meal is optimal for most active individuals. This amount, distributed evenly throughout the day, ensures a consistent supply of amino acids for muscle repair and growth. Some studies even suggest that pre-sleep casein protein intake (30–40 g) can increase overnight MPS and aid recovery during the longest fasting period.

Optimal Protein Timing and Distribution

While the concept of a very narrow "anabolic window" immediately post-exercise has been largely debunked, timing remains important for maximizing daily protein synthesis. Spreading protein intake consistently throughout the day, every 3–5 hours, is the most effective strategy. This regular intake keeps a steady supply of amino acids in the bloodstream, supporting ongoing repair and synthesis. The most important factor, however, is meeting your total daily protein goal, not hitting a rigid post-workout deadline.

High-Quality Protein Sources

To meet elevated daily protein needs, a variety of high-quality sources should be prioritized. High-quality proteins are rich in essential amino acids, particularly leucine, which is a key stimulator of MPS.

Animal-Based: Lean meats (chicken, turkey), fish (salmon, tuna), eggs, dairy (milk, Greek yogurt, cottage cheese).
Plant-Based: Tofu, legumes, beans, nuts, and seeds. Combining different plant-based proteins can provide a complete amino acid profile.
Supplements: Whey protein offers rapid absorption, making it a good post-workout option, while slower-digesting casein is ideal before bed.

Protein Needs Comparison for Athletes


Category	Daily Protein Intake (g/kg body weight)	Timing Recommendations	Key Consideration
Sedentary Adults (RDA)	0.8 g/kg/day	N/A	Meets basic needs; insufficient for active individuals.
Endurance Athletes	1.4–1.8 g/kg/day	Consistent intake every 3–5 hours; small amount during long races.	Supports muscle repair and recovery after long bouts of exercise.
Strength/Power Athletes	1.6–2.2 g/kg/day	Target 20–40g per meal, distributed throughout the day.	Maximizes muscle protein synthesis and hypertrophy.
Caloric Deficit Athletes	2.0–2.5 g/kg/day (higher end of range)	Frequent, small doses to preserve lean muscle mass.	Prevents loss of muscle tissue during periods of weight loss.

Factors Influencing Individual Protein Needs

Several variables can affect your optimal protein intake:

Age: Older adults may require a higher protein intake (around 1 g/kg/day) because of reduced absorption efficiency and a higher risk of muscle loss.
Training Intensity and Volume: High-volume or high-intensity training increases muscle breakdown and recovery needs, thus requiring more protein.
Body Composition: Heavier individuals with more lean muscle mass will naturally require a higher total gram amount of protein.
Calorie Balance: In a calorie surplus, protein needs may be slightly lower for muscle gain, but during a deficit, intake should increase to protect muscle.

Conclusion

Understanding how much protein is needed for MPs—whether you interpret it as Marathon Participants or Muscle Protein Synthesis—is critical for any athlete's success. The key is moving beyond the standard RDA for sedentary individuals and tailoring your intake to your specific activity level. For endurance athletes, a daily intake of 1.4–1.8 g/kg is recommended, while strength athletes can benefit from 1.6–2.2 g/kg. The timing of protein intake, while less critical than total daily intake, can still be optimized by spreading consumption throughout the day and considering a dose post-exercise and before bed. Always consult a sports dietitian or physician to create a plan that fits your individual needs and goals.

Explore more on the science of sports nutrition for further insights into optimizing your diet for athletic performance.

Frequently Asked Questions

In most fitness and nutrition contexts, "MP" is likely a typo for "MPS" (Muscle Protein Synthesis) or an abbreviation for "Marathon Participant." It is important to clarify the context to understand the specific protein needs.

Endurance athletes need 1.4–1.8 g/kg/day for muscle repair, while strength athletes typically aim for a higher range of 1.6–2.2 g/kg/day to maximize muscle protein synthesis and growth.

Whole food sources should be the priority, providing a wide array of nutrients. Supplements like whey or casein can be a convenient way for athletes to meet higher daily protein targets, especially around workouts or before bed.

While total daily protein intake is the most important factor, distributing protein evenly throughout the day (every 3–5 hours) can optimize muscle protein synthesis. The immediate post-workout 'anabolic window' is now believed to be much broader than previously thought.

The body's ability to utilize amino acids for muscle protein synthesis plateaus after consuming around 20–40 grams of high-quality protein in a single meal. Consuming more than this in one sitting may lead to increased amino acid oxidation for energy or other metabolic processes.

Generally, protein recommendations are based on body weight (g/kg), and recent studies suggest there are no significant sex-based differences in protein needs when accounting for body mass and activity level. However, hormonal status and other individual factors can play a role.

During a very long endurance event, consuming a small amount of protein (5–10 g/hour) can help mitigate muscle breakdown, curb hunger, and provide an alternate energy source when carbohydrate stores run low.