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July 30, 2024 • 2hr 17min
#093 Dr. Luc van Loon: Optimizing Protein Intake & Distribution for Muscle Growth
FoundMyFitness
Dr. Luc van Loon is a professor of physiology of exercise and nutrition at Maastricht University in the Netherlands. He is renowned for his research on protein metabolism, muscle adaptation to exercise, and sports nutrition. In this episode, Dr. van Loon discusses the latest science on protein requirements, muscle protein synthesis, resistance training adaptations, and nutritional strategies to optimize muscle health and performance.
#093 Dr. Luc van Loon: Optimizing Protein Intake & Distribution for Muscle Growth
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Key Takeaways
- Protein turnover is constant in the body - All tissues, including muscle, are constantly being broken down and rebuilt at a rate of 1-2% per day. This allows tissues to adapt to use and is why we need a regular intake of dietary protein.
- The 0.8 g/kg protein RDA is likely too low for optimal health - This was based on nitrogen balance studies and represents a minimum to avoid deficiency, not an optimal intake. Higher intakes of 1.2-1.6 g/kg may be beneficial, especially for active individuals.
- Protein quality and quantity both matter - Animal proteins are generally higher quality due to amino acid profiles, but plant proteins can be combined effectively. Higher quantities can compensate for lower quality to some degree.
- Muscle protein synthesis is maximized with ~20-25g of high quality protein per meal - This stimulates synthesis for 4-6 hours. Evenly distributing protein intake across 3-4 meals per day is likely optimal for most people.
- Exercise increases muscle protein synthesis and improves nutrient partitioning - Physical activity makes muscles more sensitive to the anabolic effects of protein for up to 24-48 hours after a workout.
- Cold water immersion may blunt muscle adaptations to resistance training - Cooling muscles immediately after training reduced protein synthesis in studies. Waiting several hours after training to do cold exposure may be preferable.
- The benefits of collagen supplements are still unclear - While collagen provides glycine and proline, there is limited evidence it increases collagen synthesis in muscle or other tissues more than other proteins. More research is needed.
Introduction
Dr. Luc van Loon is a professor of physiology of exercise and nutrition at Maastricht University in the Netherlands. He is renowned for his research on protein metabolism, muscle adaptation to exercise, and sports nutrition. In this episode, Dr. van Loon discusses the latest science on protein requirements, muscle protein synthesis, resistance training adaptations, and nutritional strategies to optimize muscle health and performance.
Topics Discussed
Protein Requirements and Turnover (0:00)
Dr. van Loon explains that all tissues in the body, including muscle, are constantly being broken down and rebuilt at a rate of about 1-2% per day. This equates to completely renewing muscle tissue every 50-100 days. This constant protein turnover allows tissues to adapt to use - growing larger with resistance training or smaller with disuse.
The current Recommended Dietary Allowance (RDA) for protein intake is 0.8 g per kg of body weight per day. However, Dr. van Loon notes this was established based on nitrogen balance studies and represents a minimum to avoid deficiency, not necessarily an optimal intake:
- The 0.8 g/kg recommendation assumes people can adapt to lower intakes
- It doesn't account for potential benefits of higher intakes
- Most healthy adults easily consume 1-1.3 g/kg without trying
- Athletes and very active individuals may benefit from 1.6 g/kg or higher
He emphasizes that the body can adapt to varying protein intakes, so there is likely not one universal optimal intake for everyone. Context matters - factors like activity level, age, and goals all influence individual protein needs.
Muscle Protein Synthesis and Meal Timing (34:04)
Dr. van Loon discusses research on optimizing muscle protein synthesis through protein intake and meal timing:
- About 20-25g of high quality protein maximally stimulates muscle protein synthesis for 4-6 hours in young healthy people
- This suggests evenly distributing protein intake across 3-4 meals per day is likely optimal for most
- Consuming protein before bed can stimulate overnight muscle protein synthesis
- Very high single doses (e.g. 100g) may prolong the anabolic response but are likely unnecessary for most people
He notes that while meal timing can be optimized, consistency of adequate protein intake and resistance training over time is most important for muscle adaptation.
Protein Quality and Sources (56:39)
The discussion covers differences between protein sources:
- Animal proteins are generally higher quality due to amino acid profiles
- Plant proteins can be lower in certain amino acids but can be combined effectively
- Whey protein is rapidly digested and high in leucine, making it very effective for stimulating muscle protein synthesis
- Casein is more slowly digested but can provide a more prolonged amino acid elevation
- Egg protein is also high quality and well-absorbed
Dr. van Loon emphasizes that while protein quality matters, quantity can compensate to some degree. Getting adequate total protein is most important for the average person.
Exercise and Protein Metabolism (1:17:20)
Physical activity significantly impacts how the body responds to protein intake:
- Exercise increases muscle protein synthesis and breakdown
- It makes muscles more sensitive to the anabolic effects of protein for 24-48 hours
- This allows more efficient use of dietary protein for muscle reconditioning
- Regular exercise is crucial for maintaining muscle mass, especially with aging
Dr. van Loon stresses that exercise is more potent than hormonal changes for muscle adaptation. Even in situations of low testosterone, resistance training can increase muscle mass and strength.
Cold Water Immersion and Muscle Adaptations (1:40:53)
The conversation covers research on how cold water immersion after resistance training may impact muscle adaptations:
- Cooling muscles immediately after training reduced protein synthesis in studies
- This effect was seen even when measured over two weeks of training
- Cold exposure may be more appropriate for recovery from endurance or high-impact activities
- Waiting several hours after resistance training to do cold exposure may be preferable
Dr. van Loon notes more research is needed on optimal timing of cold exposure for different training goals.
Collagen Supplements (1:50:03)
The potential benefits of collagen supplements are discussed:
- Collagen is high in glycine and proline but lower in essential amino acids compared to other proteins
- Studies have not shown collagen increases muscle protein synthesis more than other proteins
- There is limited evidence it increases collagen synthesis in connective tissues
- Small amounts may reduce joint pain in some studies, but mechanisms are unclear
- More research is needed on potential benefits for skin, tendons, and other collagen-rich tissues
Dr. van Loon emphasizes that while collagen provides certain amino acids, its superiority to other protein sources for tissue health is not yet proven.
Conclusion
This wide-ranging discussion with Dr. Luc van Loon provides an in-depth look at the current science of protein metabolism and muscle adaptation. Key takeaways include the importance of adequate protein intake distributed across the day, the powerful effects of resistance exercise for muscle health, and the need for more research in areas like collagen supplementation. While many questions remain, it's clear that combining sufficient high-quality protein intake with regular resistance training is crucial for maintaining muscle mass and function throughout life.
