Protein amount, quality and timing | Dr Don Layman

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In Episode #236, I’m joined by Dr Donald Layman to hone in on protein amount, quality, and timing.

“Functional mobility, metabolic health, and muscle are far more important than what most people give it credit for.”

There is endless online dialogue on protein. We continue to see bold claims from every direction; some influential figures spout that protein is damaging to long-term health, while others push supplements and extreme diets in favour of increasing protein intake.

We’ve examined protein on The Proof before, but today I am joined by Don Layman, PhD to offer clarity and open on a new perspective: how does protein interact with skeletal and metabolic health?

Dr Donald Layman is a leading researcher on protein, nutrition for athletic performance, obesity, diabetes, and cardiovascular health. With a highly respected career spanning over 40 years, Dr Layman has received numerous awards for his research and nutrition teaching. He is Professor Emeritus in the Department of Food Science & Human Nutrition at the University of Illinois at Urbana-Champaign, and brings a lifetime of research and education to today’s conversation.

“[Factors that determine aging] are somewhat in our DNA, but we can overcome that with the right kinds of exercise and protein, and certainly flatten the curve.”

In this episode, we delve into the interaction between protein consumption, skeletal muscle, and metabolic health. We examine age related changes to muscle, muscle protein synthesis, and longevity. Dr Layman also provides guidance on how much protein to consume and at what time.

Specifically, we cover:

  • Intro (0:00)
  • Muscle & Metabolic Health (5:00)
  • Moderate vs HIIT Training (14:00)
  • Are Aging Outcomes Genetic? (16:29)
  • Longevity vs Vitality (19:15)
  • Muscle Protein Synthesis (24:40)
  • Is the Protein RDA Sufficient? (43:03)
  • Protein Intake for Aging (56:05)
  • Why Leucine (59:48)
  • Longevity and Protein (1:03:33)
  • Cardiovascular Disease (1:16:08)
  • Protein Distribution (1:25:30)
  • Questionable Industry Funding (1:29:17)
  • Meal Timing (1:34:09)
  • Protein Threshold (1:39:33)
  • Danger of Cold Therapy (1:43:26)
  • Important Supplements (1:46:20)
  • Chronic Kidney Disease (1:49:20)
  • Outro (1:52:41)

Having followed Dr Layman’s work for a long time, it was great to have him on the show today. As an open and informed discussion – including some points where our views didn’t identically align – there is certainly room for many more conversations. I look forward to having Dr Layman back on the show in future.

To connect with Donald Layman, PhD, you can find him on Twitter. Check out his website,, to learn more about metabolic health.

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Enjoy, friends.


More about Donald Layman, PhD

Dr. Donald Layman is Professor Emeritus in the Department of Food Science & Human Nutrition at the University of Illinois at Urbana-Champaign. Dr. Layman served on the faculty at the University of Illinois from 1977 – 2012. Dr. Layman has been a leader in research about protein, nutrition for athletic performance, obesity, diabetes and cardiovascular health. Dr. Layman has over 100 peer-reviewed publications. He has received numerous awards for his research from the American Society for Nutrition and the National Institutes for Health and for his nutrition teaching. Dr. Layman served as Associate Editor of The Journal of Nutrition and the Journal of Nutrition Education and Behavior and on the editorial boards of Nutrition & Metabolismand Nutrition Research and Practice. Dr. Layman has an extensive consulting background including work with NASA, the Shriners Children’s Hospital, the US Air Force plus numerous food companies and organizations including Kraft Foods, Nestlé, Agropur, and the National Dairy Council. Dr. Layman earned his B.S. and M.S. degrees in chemistry and biochemistry at Illinois State University and his doctorate in human nutrition and biochemistry at the University of Minnesota.

Supporting studies

For notes and reflections on studies mentioned, make sure to watch on YouTube.

  • Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets: A Systematic Review and Meta-Analysis PMID: 30383278
  • Protecting muscle mass and function in older adults during bed rest PMID: 19898232
  • 2021 Dietary Guidance to Improve Cardiovascular Health: A Scientific Statement From the American Heart Association • PMID: 34724806
  • A high protein moderate carbohydrate diet fed at discrete meals reduces early progression of N-methyl-N-nitrosourea-induced breast tumorigenesis in rats • PMID: 20148110
  • Antiaging diets: Separating fact from fiction • PMID: 34793210
  • Consumption of ultra-processed foods and associated sociodemographic factors in the USA between 2007 and 2012: evidence from a nationally representative cross-sectional study • PMID: 29525772
  • Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults • PMID: 24477298
  • Elevated LDL-cholesterol levels among lean mass hyper-responders on low-carbohydrate ketogenic diets deserve urgent clinical attention and further research • PMID: 36351849
  • International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine • PMID: 28615996
  • Is There a Postworkout Anabolic Window of Opportunity for Nutrient Consumption? Clearing up Controversies • PMID: 30702982
  • Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise • PMID: 16424142
  • Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population • PMID: 24606898
  • Mortality and cause of death in hip fracture patients aged 65 or older – a population-based study • PMID: 21599967
  • mTOR as a Key Regulator in Maintaining Skeletal Muscle Mass • PMID: 29089899
  • Normal LDL-Cholesterol Levels Are Associated With Subclinical Atherosclerosis in the Absence of Risk Factors • PMID: 29241485
  • Optimal low-density lipoprotein is 50 to 70 mg/dl: lower is better and physiologically normal • PMID: 15172426
  • Postexercise cooling impairs muscle protein synthesis rates in recreational athletes • PMID: 31788800
  • Protein intake trends and conformity with the Dietary Reference Intakes in the United States: analysis of the National Health and Nutrition Examination Survey, 2001-2014 • PMID: 29931213
  • The Isocaloric Substitution of Plant-Based and Animal-Based Protein in Relation to Aging-Related Health Outcomes: A Systematic Review • PMID: 35057453
  • The underappreciated role of muscle in health and disease • PMID: 16960159
  • Trends in lipids and lipoproteins in US adults, 1988-2010 • PMID: 23073951
  • You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local – by Hannah Ritchie

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