Dr. Lonsdale was educated in England, graduating from London University with the degree MB BS. After National Service in the RAF as a medical officer he became a family physician under the National Health Service. He immigrated to Canada in 1957 and in 1960 he was accepted as a pediatric resident at Cleveland Clinic, Cleveland, Ohio. In 1962 he was appointed to the pediatric staff where his clinical research led to his commitment to uncovering the connections between thiamin metabolism and metabolic brain disease. Before retirement he was a Fellow of the American College of nutrition and a Certified Nutrition Specialist.