JOIN USA team at Cambridge University says that humans are past their peak and that modern-day people are 10 per cent smaller and shorter than their hunter-gatherer ancestors, the Daily Mail reported.
The decline, say the scientists, has happened over the past 10,000 years. They blame agriculture, with restricted diets and urbanisation compromising health and leading to the spread of disease.
The theory has emerged from studies of fossilised human remains found in Africa, Europe and Asia.
The earliest, from Ethiopia, date back 200,000 years, and were larger and “more robust” than their modern-day counterparts, Dr Marta Lahr, an expert in human evolution, was quoted as saying.
Fossils found in Israeli caves and dating from 120,000 to 100,000 years ago, reveal people who were tall and muscular, a pattern that continued uninterrupted until relatively recent times.
An average person 10,000 years ago weighed between 12st 8lb and 13st 6lb. Today, the average is between 11st and 12st 8lb, according to their findings.
“We can see that humans have continually evolved but in body size it is not until the last 10,000 years that they have changed substantially, so the question is why this should have happened,” Dr Lahr said.
The timing points to the switch from a hunter-gatherer lifestyle to agriculture, which began 9,000 years ago. While farming would have made food plentiful, focussing on a smaller number of foodstuffs could have caused vitamin and mineral deficiencies that stunted growth. In China, early farmers relied on cereals which lack niacin, a B vitamin vital for growth. However, the rise of agriculture does not explain why brains are also shrinking.