A new study from the UK, published by The Royal Society and led by Professor Lewis Halsey of Roehampton University, revealed that over the past century, men have increased in height and weight at twice the rate of women. The research analyzed vast amounts of data from the World Health Organization and other sources dating back to 1900.
The study examined the variation in height and weight of individuals based on the evolution of living conditions, evaluated using the Human Development Index (HDI), which is based on life expectancy, years of education, and per capita income. The researchers found that for every 0.2 increase in the HDI, women measured on average 1.7 centimeters taller and weighed 2.7 kilograms more, while men experienced increases of approximately 4.03 centimeters in height and 6.48 kilograms in weight.
"We have an insight into how sexual selection has shaped the male and female body and how the improvement of the environment, in terms of food and reduction of the morbidity burden, has freed us from our shackles," said Professor Lewis Halsey.
The study suggests that men may be more sensitive to environmental improvements, such as better nutrition and health care. The difference in height and weight between men and women growing up in conditions with fewer environmental challenges is greater than in environments where such challenges are common, indicating that environmental factors, including nutrition and health, play a crucial role in physical development.
In the UK, the researchers observed notable changes in average heights over the past century. The study found that in the first half of the century, the average height of women increased by 1.9% from 159 centimeters to 162 centimeters. In contrast, the average height of men increased by 4% from 170 centimeters to 177 centimeters. This data highlights the disparity in growth rates between the genders.
"To put this in perspective, about one in four women born in 1905 was taller than the average man born in 1905, but that figure fell to about one in eight for those born in 1958," said Halsey in an interview with The Guardian.
The study's results are consistent with previous work that found women prefer taller men more than men prefer shorter women. In the journal Biology Letters, the research team speculates that women's sexual preferences may be influencing a tendency towards larger, more muscular men. This suggests that sexual selection may be contributing to the observed differences in growth rates.
"Women may find men's height attractive because being tall is associated with being healthier and more handsome," explained Halsey, as reported by Milliyet. This perception reflects the idea that taller stature in men is linked to better health and vitality, traits that may be favored in mate selection.
However, the researchers also noted that with the onset of the obesity epidemic, "large" no longer always means "muscular," as reported by Kompas. This indicates that increased weight may not necessarily correspond to better health, reflecting the complexity of interpreting these trends.
The study indicated that men may be more sensitive to infection-related diseases and nutritional deficiencies than women due to being taller, which could hinder their development in environments with greater environmental challenges. This heightened susceptibility may contribute to the greater variation in men's physical development based on environmental conditions.
"The faster growth of men is 'stunning' and the difference is 'striking,' indicating their sensitivity to nutritional conditions," commented Professor Michael Wilson, as reported by BFMTV. He added, "It seems that investment in larger body size by males is sensitive to nutritional conditions. When men grow up eating energy-rich foods, their bodies grow larger, to a greater extent than women."
The researchers emphasized that health and nutrition have an influence on growth, alongside genetics. Experts say that genes determine our growth potential by 80 percent, making genetics the main factor determining a person's height. However, environmental factors such as access to quality food and healthcare play important roles in realizing that potential.
The study also noted that taller people tend to earn more money but are also more vulnerable to various types of cancer because they have more cells at risk of mutation.
Several studies have demonstrated that human height is reaching a plateau, indicating that future changes in average heights may be minimal as populations reach their genetic growth potential under optimal environmental conditions.
This article was written in collaboration with generative AI company Alchemiq