Remaining at Kings College in the 1930s, McCance conducted research on himself, studying the physiological effects of salt.

This would lead to suffering in the volunteers including cramps and shortness of breath as well as anorexia and nausea.

In 1936, he delivered the Goulstonian Lecture to the Royal College of Physicians, on the subject of Medical problems in mineral metabolism,[4] the keystone based on his research on salt deficiency.

[2] He wrote the long-standard text and reference book The Chemical Composition of Foods in 1940 in collaboration with his colleague Elsie Widdowson.

McCance and Widdowson played a leading part in wartime rationing and 1940s government nutrition efforts.