Animal and Plant Proteins in the Human Diet

This CAST paper examines the nutritional and environmental dimensions of animal- and plant-sourced proteins, highlighting their complementary roles in human health. It emphasizes the need for balanced strategies that optimize amino acid quality, accessibility, and sustainability to address malnutrition and support global food security.

Shengfa F. Liao¹,*, Jeffery K. Tomberlin², Samer W. El-Kadi³, and Luis O.Tedeschi⁴

¹Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS ; ²Department of Entomology, Texas A&M University, College Station, TX; ³School of Animal Sciences, Virginia Tech, Blacksburg, VA; ⁴Department of Animal Science, Texas A&M University, College Station, TX; *Corresponding author and Chair of the task force.

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Why It Matters

Protein is essential for human health, yet the way it is produced and consumed intersects with global challenges—nutrition, food security, sustainability, and equity. No single protein source perfectly meets human amino acid needs, and relying exclusively on either plant or animal proteins can lead to nutritional gaps or unintended consequences. This paper provides evidence-based guidance on combining complementary protein sources to achieve balanced diets while considering environmental impacts. By understanding protein quality, digestibility, and nutrient density, stakeholders can make informed decisions that promote health and sustainability worldwide.

Key Messages for Media

Why this paper matters: It clarifies widespread confusion about protein quality and sustainability.
The story angle: Balanced diets—not “plant vs. animal”—are key to health and environmental goals.
What’s new: Evidence-based strategies for combining protein sources and emerging alternatives.
Why now: Global protein demand is rising, and misinformation risks poor health and policy choices.
Impact: This paper equips journalists to report accurately on nutrition and sustainability debates.

Key Messages for Policymakers

Why this paper matters: Policy decisions on dietary guidelines and sustainability hinge on accurate science.
The challenge: Over-simplified recommendations (e.g., “plant-only”) can lead to nutrient gaps and unintended consequences.
What’s at stake: Global disparities in protein access, environmental impacts, and public health outcomes.
Action points: Support diverse protein sources, invest in sustainable production, and promote evidence-based dietary guidance.
Impact: Informed policies can reduce malnutrition, improve health equity, and mitigate environmental risks.

Authors

Shengfa F. Liao – Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS (Corresponding author and Chair of the task force)
Jeffery K. Tomberlin – Department of Entomology, Texas A&M University, College Station, TX
Samer W. El-Kadi – School of Animal Sciences, Virginia Tech, Blacksburg, VA
Luis O. Tedeschi – Department of Animal Science, Texas A&M University, College Station, TX

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Introduction

The Council for Agricultural Science and Technology (CAST) is pleased to present Animal and Plant Sourced Proteins as Part of a Balanced Human Diet, reflecting its mission to deliver credible, science-based information on food and agriculture.

Protein is vital for human health, growth, and development, yet its production and consumption intersect with global challenges—food security, nutrition, sustainability, and cultural preferences. Communities worldwide must meet rising protein needs while balancing nutritional quality, environmental impact, and equitable access.

This paper synthesizes expert analysis of these complexities, examining the roles of animal- and plant-sourced proteins, their nutritional value, environmental footprints, and strategies for a balanced, sustainable approach.

By providing evidence-based insights, CAST aims to inform policymakers, educators, industry leaders, and the public, fostering science-driven decisions for healthier people and a more sustainable planet.

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