When former prime minister Scott Morrison announced Dr James Muecke as Australian of the year on a January night in Canberra in 2020, the recipient was delighted, honoured and surprised. But possibly not as surprised as those present when the Adelaide ophthalmologist, after a few words of thanks, launched into a speech that was more attack than acceptance.

His target was the class of soluble, crystalline, sweet-tasting carbohydrates that we call sugar. More pointedly, the deleterious effect of sugar on human health. “This year,” he said, “I want to challenge our perception of sugar, our relationship with sugar, and the impact that it has on the development of diabetes.”