Research carried out as part of the Norwegian University of Science and Technology’s Industrial Ecology Programme looked at changes in the adult population of 186 countries between 1975 and 2014.
The study is the first to analyze “the role of human populations’ physical characteristics from a longitudinal perspective, beyond mere population numbers, as a driver of global food demand.”
The research found that the average global adult is 14 percent heavier, 1.3 percent taller, 6.2 percent older, and has 6.1 percent higher caloric requirements than the average global adult in 1975. Some of the highest and lowest increases were found in countries in Africa, Central Asia, and the Middle East — showing the great disparities between some nations in these regions. And while height increased globally overall, 65 out of the 186 countries included in the research showed declining average height.
“Based on the discovered trends, feeding nine billion people in 2050 will require significantly more total calories than feeding the same people today,” stated Professor Daniel B. Müller and colleagues Felipe Vásquez and Gibran Vita in an open access article for the Sustainability journal. Though older adults tend to require less caloric intake, the effect of an ageing population is not enough to counteract the increased food demand of supporting heavier, taller people.
Global human consumption increased by 129 percent between 1975 and 2014. “Population growth was responsible for 116 percent, while increased weight and height accounted for 15 percent,” wrote Steinar Brandslet for Gemini. “Older people need a little less food, but an ageing population results in only two percent less consumption.”
Müller and his team note that during the 20th century, global life expectancy rose from 36 to 70 years, and adult height increased as much as 20 centimetres for some countries in just four generations.
While increases in height can generally be seen as a sign of better nutrition, the amount of weight gain seen globally is of concern for reasons of health and environmental impact. While the researchers’ focus was not on detailed consequences of the impact of larger humans over time, they did note that “Bigger humans tend to require larger living and sitting spaces and produce more waste” — hinting at several wide-ranging ramifications.
They state that future strategies are required for reducing consumption. Each region will require its own unique strategies and assessment measures, based on unique population features and needs.