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In a nutshell
- Young children have better survival rates when animal protein makes up a larger portion of their diet due to essential amino acids and easily absorbed nutrients like iron and zinc.
- Adults over 60 benefit more from plant-based proteins, with higher life expectancy in countries where plant proteins are more prevalent in the food supply.
- The research suggests dietary guidelines should consider age-specific recommendations, especially as countries transition to more sustainable food systems.
SYDNEY — New research challenges the one-size-fits-all approach to diet, at least when it comes to protein sources. Scientists have discovered that eating meat benefits children while plant-based proteins help adults live longer.
A study by researchers at the University of Sydney examined food systems across 101 countries over nearly six decades. The findings reveal that young children survive better with more animal protein in their diet, while adults over 60 tend to live longer when consuming more plant-based proteins.
Published in Nature Communications, the study found that optimal protein balance varies with age, which has important implications as countries shift toward more environmentally sustainable food systems.
The research team examined food supply and mortality data from 1961-2018, investigating how the mix of proteins available in a country’s food system related to survival rates at different ages.
Their conclusion overturns the notion that plant-based diets are universally better. For young children, animal protein showed clear benefits. Kids had better survival rates in countries where meat, dairy, and other animal products made up more of the protein supply.
Animal foods contain complete protein with all essential amino acids plus easily absorbed forms of crucial nutrients like iron, zinc, and vitamin A—particularly important during rapid growth and development stages.
The Age Divide in Protein Benefits
For adults, especially those past middle age, the data revealed an opposite pattern. Countries with more plant protein in their food systems showed better survival rates for people over 60 and higher overall life expectancy. The benefits of plant protein became especially noticeable when combined with lower fat consumption.
Fat intake followed this same age-related pattern. Higher fat availability benefited children but appeared harmful for adults, revealing how our nutritional needs transform throughout life.
The researchers analyzed over 4,000 country-year-sex-specific life tables, accounting for economic wealth, population size, and time trends to isolate the effects of protein sources on survival rates.
We Are What We Eat
The findings raise important questions about nutrition policies. Should dietary guidelines be more age-specific? How can countries transition to sustainable food systems while meeting the distinct nutritional needs of both young and old?
For developing nations with high child mortality, ensuring adequate animal protein might remain crucial. Meanwhile, wealthier countries with aging populations might benefit from shifting toward more plant-based diets.
This research doesn’t reject environmental goals. Rather, it indicates that transitions to sustainable food systems need careful planning to maintain health across all age groups.
As countries work to reduce meat consumption, they might need approaches that ensure children still get sufficient animal protein while encouraging adults to eat more plants—balancing both health and environmental concerns across the life cycle.
“Protein is a crucial part of the human diet, but as eating habits change and developed countries look to decarbonise, where we get our protein from has come under greater scrutiny,” says Dr. Alistair Senior, the lead researcher of the study. “The knowledge that plant-based protein is associated with a longer life is really important as we consider not only how our diets impact our own longevity, but the health of the planet.”
The key takeaway? Your dietary needs change dramatically throughout your life, with the protein on your plate playing different roles in your health depending on your age.
Paper Summary
Methodology
Researchers analyzed data from 101 countries spanning 1961-2018, combining food balance sheet information from the UN Food and Agriculture Organization with mortality statistics from the Human Mortality Database. They focused on two key survivorship metrics—survival to age 5 and survival to age 60—and their relationships with national food supplies, particularly animal-based protein (ABP) versus plant-based protein (PBP). The team used generalized additive mixed models to assess associations between macronutrient supplies and age-specific mortality while controlling for time, economic factors like GDP, and population size. They weighted survivorship observations based on standard errors to mitigate model bias from outliers.
Results
After adjusting for time, population size, and economic factors, the researchers found associations between low total protein supplies and higher mortality rates across all age groups. Higher animal-based protein and fat supplies were associated with improved early-life survivorship, while later-life survival improved with increased plant-based protein and lower fat supplies. Life expectancy was maximized where plant-based protein was high and animal-based protein and fat supplies were low. The study revealed an age-dependent shift in optimal nutrition, where animal protein benefits early development but plant protein appears more advantageous for long-term adult survival.
Limitations
The study is ecological in nature, examining national-level food supply data rather than individual dietary intake. This approach cannot establish causal relationships between protein sources and mortality, and doesn’t account for within-country variations in food access or consumption patterns. The researchers acknowledge potential unaccounted confounding factors beyond GDP and time, including broader socioeconomic factors like food access, affordability, and cultural dietary preferences. The analysis also doesn’t differentiate between types of fats (saturated vs. unsaturated) or carbohydrate qualities (refined vs. complex), which could influence health outcomes independently.
Funding/Disclosures
Funding support for this research came from the University of Sydney, Faculty of Science. One author received support from the University of Sydney Horizon Program and the Australian Research Council Future Fellowship scheme. The authors declared no competing interests.
Publication Information
The study titled “Associations between national plant-based vs animal-based protein supplies and age-specific mortality in human populations” was authored by Caitlin J. Andrews, David Raubenheimer, Stephen J. Simpson, and Alistair M. Senior from the Charles Perkins Centre and School of Life and Environmental Sciences at the University of Sydney. It was published in Nature Communications, volume 16, article number 3431, on April 11, 2025.
