The effect of a 500 calorie diet on the course of psoriasis was compared to that of a regular diet in hospitalized patients for three to five weeks. Local therapy was restricted to a bland cream. Of eight patients on a regular diet, four improved, two were unchanged, and two became worse. Of eight patients on the low calorie diet, one improved and seven became worse. Two patients who received the regular followed by the low calorie diet did better on the regular diet. A severe weight reduction program appears to be of no benefit in the management of psoriasis.
Zackheim HS, Farber EM. Rapid Weight Reduction and Psoriasis. Arch Dermatol. 1971;103(2):136-140. doi:10.1001/archderm.1971.04000140022004