Global food systems are responsible for a third of all greenhouse gas emissions. These systems are being examined for ways to make them more sustainable. They are complex social-ecological networks that include all the infrastructure and procedures necessary to feed a population. One suggested change is reducing the intake of animal-based protein (ABP) and increasing plant-based protein (PBP). This change could affect the health outcomes across different age groups. The type and amount of protein play a significant role in health.
Previous studies have shown that animal proteins are associated with chronic diseases, while plant proteins may lower the risk. A recent study published in Nature Communications aimed to explore how the national ABP and PBP levels relate to age-specific mortality (ASM) using a nutritional model.
In this study, the supply of macronutrient food balance sheet (FBS) information was collected from the United Nations’ Food and Agriculture Organization Statistical (FAOSTAT) database, the value of Gross Domestic Product (GDP) per capita from the Maddison projection database 2020, and ASM from the Human Lifetable Database (HLD). The dataset contained demographic information for 101 countries between 1961 and 2018, as well as the daily per capita food supply.
The study results showed that the global protein supply of ABP to PBP ratio decreased in regions such as Western Europe and North America, whereas PBP-dominant regions like South America and South Korea showed increased ABP levels. The total protein supply increased over time, mainly due to a rise in ABP. Additionally, the ratio of ABP to PBP increased to the GDP, peaking around $12,000 per capita (2011 value). The greater GDP was associated with higher protein supply, although ABP was more predominant in lower-GDP countries. PBP was more prevalent in regions with higher carbohydrate intake, and ABP was more prevalent in areas with higher fat consumption.
The generalized additive mixed model (GAMM) showed a strong positive correlation between age-specific survivorship at age 5 (l5) and ABP, whereas PBP benefits were much weaker. l5 exhibited a positive correlation with total fat supplies. Moreover, a nonlinear correlation was observed between l5 and carbohydrate supplies. In both sexes, l5 was highest when carbohydrate intake was relatively low, at 1200 kcal/cap/day.
PBP was more effective at improving survival at age 60 (l₆₀) compared to ABP, with the highest l₆₀ observed at high PBP and lower ABP levels.  l₆₀ showed a negative correlation with fat supplies. For both males and females, a moderate carbohydrate intake of ~1500 kcal/day supported the best later-life survival, particularly in males. Life expectancy increased with high PBP and low ABP and fat, especially under conditions of overall low protein and fat intake. ABP supported better survival in early life, whereas PBP was linked to better survival from early adulthood. After age 70, the difference between the two diets decreased.
This study’s limitations include residual confounding, ecological fallacy, reliance on food supply data rather than actual intake, limited nutrient details, and unmeasured socio-economic and dietary differences across populations.
In conclusion, this study highlights that the optimal protein-to-fat ratio in national food supplies associated with the lowest mortality differs by age. This study suggests reducing ABP may require age-specific adjustments to optimize both health outcomes and environmental sustainability.
Reference: Andrews CJ, Raubenheimer D, Simpson SJ, et al. Associations between national plant-based vs animal-based protein supplies and age-specific mortality in human populations. Nat Commun. 2025;16:3431. doi:10.1038/s41467-025-58475-1
