After receiving her master's degree, MacArthur spent three years during
World War II as a researcher at the
Commonwealth Scientific & Industrial Research Organisation in
Canberra where she helped develop containers to deliver food for troops in the tropics (1943–1945). Following training at the
Australian Institute of Anatomy, in 1947 she joined the Nutrition Expedition to New Guinea conducted by the Commonwealth Department of Health. In 1948, she served as a nutritionist in the
American-Australian Scientific Expedition to Arnhem Land to study the ecology of indigenous nomads in the far north-east of Australia's
Northern Territory. In connection with her Ph.D., MacArthur undertook field research on the Kunimaipa people of Papua, communicating with them in their own language as she studied their nutritional habits. From 1958 to 1960, she worked as a social anthropology consultant to the government of Malaya on behalf of the World Health Organization. She then spent a year as nutrition consultant for Indonesia on an assignment from the United Nations Food and Agriculture Organization. ==References==