Study of the Effect of Diet in Overweight or Obese Patients With Psoriasis on Light Therapy

This study involves the use of diet as a therapeutic agent in subjects with obesity and psoriasis who are eligible for and willing to undergo phototherapy. Subjects undergoing phototherapy alone will be compared to subjects randomized to receive phototherapy and dietary modification with the goal of weight loss. The primary objective is to determine the success rate of weight loss programs in the setting of psoriasis. Secondary objectives include evaluating the effect of weight loss on efficacy of narrow band ultraviolet B phototherapy, and assessing the efficacy of lower carbohydrate and low fat diets in psoriatic patients.