Professor Nestel’s academic appointments include:

1. Professorial Fellow, John Curtin School of Medical Research, Canberra 1965–75.
2. Deputy Director of Baker Heart Research Institute 1976–1985.
3. Chief, CSIRO Division of Human Health and Nutrition and Clinical Professor of Medicine Flinders University Adelaide 1986–95, 1996–
4. Senior Principal Research Fellow Baker Institute and currently Senior Scientist Baker Heart and Diabetes Institute.
5. He was also Honorary Cardiologist Alfred Hospital, Melbourne 1996–2010.
6. He held Visiting Professorial appointments at University of California San Francisco and San Diego, and at Rockefeller University, New York, and worked at National Institutes of Health USA.

Major scientific research included cardiovascular prevention, therapy and public health, lipoprotein and cholesterol metabolism, nutrition and diabetes. He received several international and national Prizes. He founded the Australian Atherosclerosis of Australia and served as its President and as Vice-President of the International Union of Nutritional Sciences. He is a Fellow of the Academy of Technological Sciences & Engineering.

He has published 490 peer reviewed papers. He served as Chair/member of national and international scientific committees. His recognition for excellence in cardiovascular prevention and research has been recognised as Officer of Australia (AO) and Centenary Medal.