The Consensus on Protein Intake for Optimal Muscle Growth and Maintenance

By ,
on Sep 8, 2023

This blog post is based on a landmark position statement from the International Society of Sports Nutrition (ISSN), a leading authority in the field of sports nutrition.

First published in 2017 and only recently made available online in late 2022, this ISSN statement acts as a cornerstone in sports nutrition science and provides much-needed clarity in the often confusing world of dietary advice.

Highlights from the ISSN's Statement: Your Blueprint for Protein Intake for Optimal Muscle Growth

  1. Protein and Exercise Synergy: An acute exercise stimulus, especially resistance exercise, and protein ingestion are synergistic for stimulating muscle protein synthesis (MPS) when protein is consumed before or after resistance exercise.
  2. Optimal Daily Protein Intake: To build and maintain muscle mass through a positive protein balance, an overall daily protein intake in the range of 1.4–2.0 g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals. This recommendation aligns with the Acceptable Macronutrient Distribution Range by the Institute of Medicine for protein.
  3. Protein Timing and Distribution: Protein doses should ideally be evenly distributed, every 3–4 hours, across the day to maximize MPS. The anabolic effect of exercise is long-lasting (at least 24 hours), but likely diminishes with increasing time post-exercise.
  4. Protein Quality and Sources: For optimal results, focus on whole food sources of protein that contain all essential amino acids (EAAs), especially leucine. General recommendations are 0.25 g of high-quality protein per kg of body weight, or an absolute dose of 20–40 grams per serving.
  5. Leucine and EAAs: Acute protein doses should aim to contain 700–3000 mg of leucine and/or a higher relative leucine content, in addition to a balanced array of EAAs.
  6. Rapidly Digested Proteins: Proteins that are rapidly digested and contain high proportions of EAAs are most effective in stimulating MPS.
  7. Endurance Athletes: While the focus should be on adequate carbohydrate intake, the addition of protein may help offset muscle damage and promote recovery.
  8. Pre-Sleep Protein: A pre-sleep casein protein intake of 30–40 g can increase overnight MPS and metabolic rate without influencing lipolysis.
  9. Safety and Health: There is no evidence to suggest that high protein intake has harmful effects on kidney or liver function. Protein intake may even have beneficial effects on body composition, immune function, and oxidative stress.
  10. Emerging Evidence: There is novel evidence suggesting that higher protein intakes (>3.0 g/kg/d) may have positive effects on body composition in resistance-trained individuals, specifically in promoting the loss of fat mass.
  11. Supplementation: While it's possible for active individuals to meet their daily protein needs through whole foods, supplementation can be a practical way to ensure adequate protein quality and quantity, especially for athletes who complete high volumes of training.

The Science of Protein and Muscle Protein Synthesis (MPS)

Understanding how your body uses protein is crucial for anyone interested in maintaining muscle, improving athletic performance, or simply being proactive about their health. Muscle Protein Synthesis (MPS) is the biological process by which muscle tissue is constructed and repaired. Consuming protein either before or after resistance exercise enhances the body's ability to stimulate MPS.

The ISSN recommends that protein be consumed in close temporal proximity to resistance exercise to maximize muscle protein synthesis (MPS) (Jäger et al., 2017, Journal of the International Society of Sports Nutrition, 14, 20).

How Much Protein Do You Need?

Navigating the complex world of dietary advice can be overwhelming, especially when it comes to figuring out the optimal protein per lb/kg to maintain muscle. Thankfully, the ISSN provides clear, evidence-based guidelines to help you make informed decisions.

The ISSN suggests a daily protein intake for those engaged in regular resistance exercise to be in the range of 1.4 to 2.0 g/kg/day (Jäger et al., 2017, Journal of the International Society of Sports Nutrition, 14, 20).

Example for Men: 176-pound male (approx 80 kg).

  • Lower limit: 112 grams of protein per day
  • Upper limit: 160 grams of protein per day

Example for Women: 132-pound female (approx 60 kg).

  • Lower limit: 84 grams of protein per day
  • Upper limit: 120 grams of protein per day

When More Might be Better

Higher protein intakes (>3.0 g/kg/d) may offer additional benefits, particularly in resistance-trained individuals, promoting the loss of fat mass.

Whole Foods vs. Supplements: The ISSN Perspective

While protein supplements, especially whey isolates, offer certain advantages, whole food sources of protein, such as lean meats, fish, dairy, and eggs, are invaluable. Eggs, in particular, are hailed as a superior protein source due to their high bioavailability and complete amino acid profile. The egg white contains approximately 3.6 g of protein, while the yolk provides an additional 2.7 g, making eggs an indispensable dietary choice.

Prime Whole Food Sources of Protein

Whole foods like meats, dairy, and legumes are rich in essential amino acids, which are the building blocks of protein. These foods are also more satiating, meaning they can help control appetite and contribute to a more balanced diet.

While supplements offer convenience, whole foods are unmatched in their nutrient profile. Below are some of the best whole food sources of protein:

  1. Chicken Breast: A staple in many diets, skinless chicken breast is lean and high in protein.
  2. Eggs: A complete protein source, a single egg contains beneficial nutrients from both the white and the yolk.
  3. Salmon: Beyond its protein content, salmon is also rich in omega-3 fatty acids.
  4. Greek Yogurt: This dense yogurt variant provides roughly 10 grams of protein per 100 grams, making it both a delicious and protein-rich snack.
  5. Quinoa: A unique plant-based complete protein, quinoa offers about 4 grams of protein per 100 grams and is also rich in essential amino acids.
  6. Lentils: A fantastic vegetarian protein source, lentils provide around 9 grams of protein per 100 grams when cooked.
  7. Tofu: Made from soybeans, tofu offers around 8 grams of protein per 100 grams and is a popular protein source in vegetarian and vegan diets.
  8. Beef Steak: Lean cuts of beef, such as sirloin or tenderloin, are dense in protein, offering approximately 25-28 grams per 100 grams.
  9. Almonds: While they're better known for healthy fats, almonds also contribute a good amount of protein, with around 6 grams per 28 grams (about 23 almonds).
  10. Cottage Cheese: A dairy favorite, cottage cheese provides roughly 11 grams of protein per 100 grams and can be a versatile addition to various dishes.

Incorporating a mix of these whole food sources in one's diet ensures a balanced protein intake, accompanied by a plethora of other essential nutrients.

Example: Meal Plan for a 43-year-old Individual Weighing 165lbs

With a foundational understanding of protein sources and intake, let's craft a practical meal plan. For a 43-year-old individual weighing 165lbs (approximately 75kg):

  • Breakfast: 3 boiled eggs (18g protein), a bowl of oatmeal (6g protein), and a glass of milk (8g protein).
  • Lunch: Grilled chicken breast (approximately 54g protein), quinoa salad (8g protein), and steamed vegetables (3g protein).
  • Snack: Greek yogurt (10g protein) and a handful of almonds (6g protein).
  • Dinner: Grilled salmon fillet (45g protein), sautéed spinach (5g protein), and lentil soup (18g protein).

This meal plan provides a total of approximately 158g of protein, which falls within the recommended range of 1.4 to 2.0 g/kg of body weight for optimal muscle maintenance and growth.

When to Use Supplements

Protein supplements can be useful in certain situations, such as:

  • When you're unable to meet your protein needs through whole foods alone.
  • For convenience when on-the-go or unable to prepare a whole-food meal.
  • For specific dietary restrictions that make it challenging to get enough protein from whole foods. However, it's crucial to view supplements as a secondary option, to fill gaps rather than replace whole foods entirely.

Meet Our AI Chatbot

Navigating personalized nutrition can be complex, but you're not alone in this journey. Meet our AI Chatbot, designed to offer personalized protein intake advice rooted in evidence-based science. Here's what sets our Chatbot apart:

  • Optimal Meal Plans for Protein Intake: Receive meal plans that are in line with the ISSN guidelines.
  • Optimal Protein Supplements: Get personalized recommendations on which types of protein supplements could be most beneficial for you.
  • Ideal Protein Intake Ranges: Using your age, sex, and body weight (both in lb and kg), the Chatbot provides customized protein intake ranges.
  • Evidence-Based: Strictly adheres to evidence-based information, aligning with the ISSN guidelines. When it can't find an answer within these guidelines, it consults only peer-reviewed and prestigious sources in the field of exercise and sports nutrition.

Chatbot in Action: A Simulated Example

User: "Hi, I'm a 30-year-old male weighing 176 pounds and I work out 4 times a week. How much protein should I consume daily?"

AI Chatbot: "Based on the ISSN guidelines, a daily protein intake in the range of 1.4–2.0 g protein/kg body weight per day is sufficient for most exercising individuals. For a 176-pound male like yourself (which is approximately 80 kg), you would need:

  • Lower limit: 112 grams of protein per day (1.4 g/kg x 80 kg)
  • Upper limit: 160 grams of protein per day (2.0 g/kg x 80 kg)

AI Chatbot Would you like to know more about optimal meal plans or protein supplements to meet these protein needs?"

AI Chatbot

A study published in JAMA found that in over 78% of cases, medical professionals preferred AI-generated answers to physician responses for quality and empathy (Shen et al., 2022).


In summary, the ISSN offers invaluable, evidence-based guidelines on the role of protein in exercise and sports nutrition. By following these recommendations, you can optimize your protein intake for muscle growth and performance improvement.

Longevity Reminders

Sarcopenia and the Importance of Protein in Aging

Sarcopenia, the age-related decline in muscle mass and strength, poses a significant threat to longevity and quality of life as we age. Starting in our 40s, we can lose up to 5% of muscle mass per decade, leading to decreased strength, mobility issues, and a reduced metabolic rate. However, maintaining adequate protein intake, especially when combined with resistance training, can mitigate the effects of sarcopenia. By prioritizing muscle health through protein consumption, we not only add years to our lives but also enhance the quality of those years, ensuring mobility, independence, and overall well-being.

The Role of Sleep and Rest in Muscle Health

Sleep and rest are often overlooked but are crucial components of muscle health and growth. During sleep, the body enters a state of recovery and regeneration, which is essential for muscle repair and growth.

Research has shown that sleep deprivation can negatively impact muscle recovery and growth. A study published in the Journal of Applied Physiology found that sleep deprivation can decrease protein synthesis, leading to muscle atrophy and impaired recovery from exercise.

Sleep deprivation can decrease protein synthesis, leading to muscle atrophy and impaired recovery from exercise (Dattilo et al., 2011, Journal of Applied Physiology, 110, 930-939).

Furthermore, sleep is essential for the production of growth hormone, a key player in muscle growth. The majority of growth hormone is released during deep sleep stages, emphasizing the importance of quality sleep for muscle health.

The majority of growth hormone is released during deep sleep stages, emphasizing the importance of quality sleep for muscle health (Van Cauter et al., 2000, Sleep, 23, 1063-1066).

In conclusion, adequate sleep and rest are as important as diet and exercise for optimal muscle health. It's recommended to aim for 7-9 hours of quality sleep per night and to ensure adequate rest days in your exercise regimen to allow for muscle recovery and growth.