Optimizing muscle protein synthesis: the crucial impact of protein quality and quantity, and the key role of resistance training | Luc van Loon, Ph.D.

Peter Attia

Apr 22, 2024

Episode description

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Luc van Loon is an internationally renowned expert in skeletal muscle metabolism. In this episode, Luc starts with an exploration of the roles of insulin and triglycerides in endurance exercise, highlighting their impact on skeletal muscle metabolism, and he offers profound insights into the significance of protein in this context. He elucidates how different protein types and forms influence muscle protein synthesis rates, exploring the nuances of protein absorption, digestibility, amino acid quality, and their implications for performance and recovery. Delving deeper, he differentiates between animal and plant protein sources, unraveling the distinctive properties of various protein types, from the differences between whey and casein to the emerging trends in collagen protein supplementation. Moreover, Luc dissects the intricate connections among physical activity, lean muscle mass, muscle protein synthesis induced by resistance training, and dietary protein.

We discuss:

  • Luc’s background and insights about fuel selection during exercise [3:30];

  • Fuel utilization during endurance exercise [9:30];

  • Fat metabolism, intramuscular lipids, and the nutritional dynamics of endurance sports [17:15];

  • The optimal window for replenishing intramuscular fat stores and glycogen post-exercise [25:15];

  • Luc’s interest in protein metabolism and exploration of amino acids' dual role as building blocks and signaling molecules in driving muscle protein synthesis [32:15];

  • How protein metabolism differs between sedentary individuals and those engaged in predominantly strength training or endurance training [38:45];

  • The basics of how proteins are digested and absorbed, and how muscle protein synthesis is measured [50:30];

  • How factors like food texture, cooking methods, and protein composition impact muscle protein synthesis, and the importance of protein distribution throughout the day [59:45];

  • Differences in whey and casein proteins, and the ability of ingested protein to stimulate muscle protein synthesis [1:03:30];

  • Dietary protein distribution and quantity for the maximization of muscle protein synthesis [1:09:00];

  • Muscle loss with age and inactivity and the importance of resistance e

Episode description

View the Show Notes Page for This Episode

Become a Member to Receive Exclusive Content

Sign Up to Receive Peter’s Weekly Newsletter

Luc van Loon is an internationally renowned expert in skeletal muscle metabolism. In this episode, Luc starts with an exploration of the roles of insulin and triglycerides in endurance exercise, highlighting their impact on skeletal muscle metabolism, and he offers profound insights into the significance of protein in this context. He elucidates how different protein types and forms influence muscle protein synthesis rates, exploring the nuances of protein absorption, digestibility, amino acid quality, and their implications for performance and recovery. Delving deeper, he differentiates between animal and plant protein sources, unraveling the distinctive properties of various protein types, from the differences between whey and casein to the emerging trends in collagen protein supplementation. Moreover, Luc dissects the intricate connections among physical activity, lean muscle mass, muscle protein synthesis induced by resistance training, and dietary protein.

We discuss:

  • Luc’s background and insights about fuel selection during exercise [3:30];

  • Fuel utilization during endurance exercise [9:30];

  • Fat metabolism, intramuscular lipids, and the nutritional dynamics of endurance sports [17:15];

  • The optimal window for replenishing intramuscular fat stores and glycogen post-exercise [25:15];

  • Luc’s interest in protein metabolism and exploration of amino acids' dual role as building blocks and signaling molecules in driving muscle protein synthesis [32:15];

  • How protein metabolism differs between sedentary individuals and those engaged in predominantly strength training or endurance training [38:45];

  • The basics of how proteins are digested and absorbed, and how muscle protein synthesis is measured [50:30];

  • How factors like food texture, cooking methods, and protein composition impact muscle protein synthesis, and the importance of protein distribution throughout the day [59:45];

  • Differences in whey and casein proteins, and the ability of ingested protein to stimulate muscle protein synthesis [1:03:30];

  • Dietary protein distribution and quantity for the maximization of muscle protein synthesis [1:09:00];

  • Muscle loss with age and inactivity and the importance of resistance e

Mindsip insights from this episode:

Combat age-related muscle loss by staying active consistently

Age-related muscle loss is not a slow decline but the result of short periods of inactivity from which an individual never fully recovers their muscle mass.

Combat anabolic resistance with consistent physical activity

A young person's leg shows 35% anabolic resistance after just one week of inactivity, suggesting physical activity is the primary driver of the muscle's ability to use protein.

Refresh your muscle proteins every 50 to 100 days for a new arm

Your muscle proteins are completely refurbished every 50 to 100 days, meaning you essentially have a new arm in that time frame.

Recognize inactive muscles store fat during exercise

During exercise, inactive muscles will actually increase their fat stores as they opportunistically take up the excess free fatty acids circulating in the blood.

Understand athlete's paradox: turnover distinguishes fat storage

The key difference between the high intramuscular fat in athletes and diabetics is turnover; athletes constantly use and replenish this fat store, while in diabetics it's a permanent storage.

Fuel muscle growth with a pre-sleep protein snack

The gut effectively digests and absorbs protein during sleep, allowing a pre-sleep protein snack to stimulate muscle protein synthesis overnight.

Reassess collagen's role in muscle connective tissue synthesis

Ingesting collagen protein does not appear to increase muscle connective tissue synthesis rates beyond what exercise and regular dairy protein already provide.

Refresh your brain every three weeks with protein turnover

The protein turnover rate of the human brain is almost three times as high as muscle, which can be translated to having a new brain approximately every three weeks.

Mince meat to enhance muscle protein synthesis

Ingesting minced meat leads to more rapid digestion and a greater muscle protein synthesis response compared to eating the same amount of meat as a whole steak.

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