#592: How Much Protein is Actually Healthy? – Eric Helms, PhD & Matt Nagra, ND

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Introduction

In this episode, the discussion turns to a deceptively simple question that sits at the centre of countless nutrition debates: how much protein do we actually need?

On one side, there are confident claims that very high protein intakes are not just beneficial but essential for maximising strength, performance, and muscle mass. On the other, equally strong assertions that the current RDA is entirely sufficient for most people, and that going beyond it is unnecessary or even harmful.

Dr. Eric Helms and Dr. Matthew Nagra work through what the evidence actually tells us when we step away from slogans and thresholds. What does 0.8 g/kg represent, and just as importantly, what does it not? At what point do higher intakes stop meaningfully improving muscle-related outcomes? And where do concerns about kidney function, longevity, and chronic disease fit when we look at long-term data rather than isolated mechanisms?

Rather than treating protein as a single number to defend or dismiss, this conversation places intake in context: training status, ageing, health outcomes, source and optimising for specific goals.

Guest Information

Dr. Matthew Nagra, ND

Dr. Matthew Nagra is a naturopathic doctor practising in Vancoucer, Canada. Outside of clinic he is a prominent nutrition science communicator, known for his evidence-based approach to diet and health questions. He has also contributed to multiple nutrition textbooks and has published peer-reviewed journal articles.

Eric Helms, PhD

Eric is the newly appointed co-director of the Sports Performance Research Institute New Zealand, based at Auckland University of Technology. He has been a research fellow and the lab lead for strength and conditioning for a long time in that institute.

He is also a coach and educator with 3D Muscle Journey (3DMJ); co-founder and author for MASS research review. He is also the author of the highly popular Muscle & Strength Pyramids set of books.

Timestamps

• [05:19] Discussion starts
• [07:18] Setting the scene: protein intake and health
• [09:38] Health outcomes and protein intake
• [10:27] Mechanistic measures vs. longitudinal outcomes
• [15:47] The RDA: purpose and limitations
• [19:19] Higher protein recommendations: where do they come from?
• [21:48] Protein intake for athletes and general population
• [27:25] Dose response and optimal protein intake
• [44:59] Statistical errors in Morton meta-analysis
• [46:07] Comparing meta-analyses: Morton, Tagawa, and Nunez
• [56:23] Mechanistic claims and protein intake
• [59:49] Nitrogen balance and protein requirements
• [01:11:55] Protein sources and health outcomes
• [01:18:13] Summarizing optimal protein intake
• [01:24:31] Key ideas segment (premium subscribers only)

Related Resources

• Join the Sigma email newsletter for free
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• Enroll in the next cohort of our Applied Nutrition Literacy course
• Dr. Helms:
  • MASS Research Review
  • Muscle & Strength Pyramids books
  • Instagram: @helms3dmj
• Dr. Nagra:
  • Instagram: @dr.matthewnagra
  • Dr. Nagra’s website
• Studies mentioned:
  • Tagawa et al., 2022 – Synergistic Effect of Increased Total Protein Intake and Strength Training on Muscle Strength: A Dose-Response Meta-analysis of Randomized Controlled Trials
  • Nunes et al., 2022 – Systematic review and meta-analysis of protein intake to support muscle mass and function in healthy adults
  • Refalo, Trexler and Helms, 2025 – Effect of Dietary Protein on Fat-Free Mass in Energy Restricted, Resistance-Trained Individuals: An Updated Systematic Review With Meta-Regression
  • Morton et al., 2018 – A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults
  • Korat et al., 2024 –  Dietary protein intake in midlife in relation to healthy aging – results from the prospective Nurses’ Health Study cohort
  • Rand et al., 2003 – Meta-analysis of nitrogen balance studies for estimating protein requirements in healthy adults
  • Walberg et al., 1988 – Macronutrient content of a hypoenergy diet affects nitrogen retention and muscle function in weight lifters
  • Pikosky et al., 2008 – Increased protein maintains nitrogen balance during exercise-induced energy deficit
  • Tipton, 2008 – Protein for adaptations to exercise training
  • Tomé and Bos, 2000 – Dietary protein and nitrogen utilization
  • The PROT-AGE Study Group recommendations
  • French et al., 2025 – The harms of high protein intake: conjectured, postulated, claimed, and presumed, but shown?
  • Glenn et al., 2024 – Dietary plant-to-animal protein ratio and risk of cardiovascular disease in 3 prospective cohorts
  • Naghshi et al., 2020 – Dietary intake of total, animal, and plant proteins and risk of all cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of prospective cohort studies
• Related episodes:
  • 454: Eric Helms, PhD – Plant or Animal Protein: Rethinking Protein & Muscle
  • 534: Are Plant-Based Meat Alternatives Healthy? – Matthew Nagra, ND
  • 362: Alistair Monteyne – Impact of Mycoprotein & Vegan Diets on Muscle Protein Synthesis
  • 564: Is Protein’s Appetite-Suppressing Power Overstated?
    

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