William Philip Trehearne James (June 27, 1938 – October 5, 2023) was a British professor.^[1]

James was born in Liverpool, England in 1938, but was grew up in Bala, Snowdonia, Wales.^[2][3] His family members were Quakers.^[3]

James attended Ackworth School and later studied medicine at UCL Medical School.^[2][1]

In 1965, James was sent by the Medical Research Council to study malnutrition in Jamaica, where he developed treatments for children with severe malnutrition and diarrhoea.^[2][1] He later became director of the Rowett Institute in 1982, a leading nutrition research institute, and worked on projects for the World Health Organization (WHO).^[2][1]

In the early 1980s, James co-authored a report by the National Advisory Committee on Nutrition Education, which provided recommendations on reducing fat, sugar, and salt intake in the British diet.^[2]

In 1995, James founded the International Obesity Task Force (IOTF) and organized the first WHO global burden analysis of obesity, highlighting the substantial disease burden associated with high Body mass index.^[2] He also established the International Association for the Study of Obesity (now the World Obesity Federation), serving as its president from 2007 to 2014.^[2]

James was elected to Fellowship of the Royal Society of Edinburgh in 1986 and appointed Commander of the Order of the British Empire (CBE) in 1993.^[2]

William Philip T James Award is named after him.^[3]

James was married to Jean Moorhouse from 1961 until his death, and they had two children.^[2][3]