An international research team analyzed a large dataset tracking changes in height and weight across regions worldwide. The researchers found that as countries became wealthier and healthier, their populations grew taller and heavier. Men, the team found, experienced that growth at twice the rate of women over the past century.
The study used data from 135,645 people (46 percent of whom were men) in 62 countries. The dataset was supplemented with statistics from Wikipedia and historical records from Great Britain dating back to 1900. The study excluded people with obesity.
What Did the Scientists Discover?
The analysis confirmed clear sexual dimorphism: men were consistently taller and heavier than women.
“Our cross-national analysis showed that as social and environmental conditions improve in countries, including a reduction in the overall burden of disease, the height and weight of people increase, but men experience this growth at twice the rate of women, leading to a more pronounced sexual dimorphism in size,” the team wrote.
Height and weight for both sexes correlated with national wealth and population health, measured by the Human Development Index (HDI). The researchers found that quality of life and environmental conditions significantly influenced those measures.
But why is this effect much more pronounced in men? The team suggests the male body may be more sensitive to living conditions. Larger bodies might require more resources or better nutrition to grow, while the environment appears to have a smaller effect on women’s body size.
The researchers also observed variability in these measures between countries. Science Alert reported that the range of weight was broader in higher-HDI countries, while height variation among men decreased as HDI rose.
The scientists suggested that men’s height could serve as a useful indicator of a population’s overall health and well-being. That gives governments a relatively straightforward metric to track.
However, the researchers acknowledged that longer-term studies are needed to confirm the patterns they identified.
“Our study combined evolutionary biology with indicators of human well-being, providing new insights into how socio-ecological factors and sexual selection shape key physical traits,” the team wrote.
The findings were published in the journal Biology Letters.
