Upon returning from France to Iran in 1951, Hedayat and his colleagues established the Hafez specialty clinic in Tehran which remained open until 1953. After long discussions with the then Minister of Health, Jahanshah Saleh, Hedayat obtained approval for a research project on Iran's workers’ health. As part of this research project, Hedayat observed malnourished Iranian girls weaving carpets in
Kerman in poor working conditions and this caused an internal revolution in him. He decided to focus on "nutrition" as the vital factor in the health and wellbeing of the Iranian people – a subject not taken seriously by the medical community at the time. Since neither he, nor his colleagues in Iran, had formally studied or specialized in the field of nutrition, Hedayat decided to study nutrition sciences overseas under Professor Colin B.S. Platt (professor of nutrition and president of Human Research Centre) at the
London School of Hygiene and Tropical Medicine (
University of London) as well as the
Medical Research Council. Hedayat's master thesis in nutrition was entitled: "A Study of Nutrition in Persia, Including a Laboratory Investigation of the Nutritive Value of Typical Dietaries." Upon his second return to Iran in 1961, Hedayat was appointed director general of Health Affairs for the Tehran province. It was during this period in his career that he established the Institute of Nutrition and Food Science of Iran (INFSI). The initiative started with modestly sized classes, few laboratories, and a library at the Firouzgar hospital in Tehran. The name of the institute was later changed to National Nutrition & Food Technology Research Institute (NNFTRI). It was during the establishment of INFSI that Hedayat became acquainted with his long-time colleague and friend, Shahab Vaez Zadeh. These two scientists pledged to work together to make the INFSI, a vital necessity for Iran, into a success. The institute, in collaboration with the nutrition section at the Embassy of France under the auspices of Professor Trémolières, organized seminars and conferences and granted scholarships to students interested in the field. The institute was to soon find international fame. United Nations entities such as
Food and Agriculture Organization (FAO),
World Health Organization (WHO), and
UNICEF started supporting the institute. These organizations provided 28 academic scholarships for staff and students. Hedayat was invited to a UNICEF conference in New York, where Sir Herbert Broadley, the former acting director-general of FAO and UNICEF's representative in Great Britain, indicated that establishment of the Institute of Nutrition and Food Science in Iran had inspired several other Middle Eastern countries to follow suit and establish similar institutes in their respective countries. As an integral part of the institute, Iran's College of Nutrition Sciences and Food Chemistry was established. Additionally, a rural research center was established in Gorg-Tapeh, a rural area in Varamin, near
Tehran. Later, in cooperation with Abdolrahim Emami, who had been sent by Hedayat to London to receive his specialty under supervision of Prof. Platt, a branch of the Nutrition Institute was established at the Esfahan University in
Esfahan, Iran. In 1970, the Iranian Diabetes Society was also established with Hedayat as a founding member and chairman of the board. ==Scientific Works==