INS and porphyria: An association between the lack of carbohydrate intake and the appearance of porphyria symptoms has long been described in both humans11,12 and rats.15,16 Conversely, high caloric intake and a higher insulin level were associated with lower biochemical disease activity.17 Furthermore, glucose treatment has an important role in the treatment of an acute attack.2 Nevertheless, while studies addressing extreme diets and carbohydrate deprivation are available, data regarding the association between controlled short-term fasts and porphyria symptoms are lacking.