Inflammatory diseases including psoriasis are associated with metabolic and cardiovascular comorbidities, including obesity and metabolic syndrome. Obesity is associated with greater psoriasis disease severity and reduced response to treatment. Therefore, targeting metabolic comorbidities could improve patients’ health status and psoriasis-specific outcomes. METABOLyx is a randomized controlled trial evaluating the combination of a lifestyle intervention program with secukinumab treatment in psoriasis. Here, the rationale, methodology and baseline patient characteristics of METABOLyx are presented. A total of 768 patients with concomitant moderate to severe plaque psoriasis and metabolic syndrome were randomized to secukinumab 300 mg, or secukinumab 300 mg plus a tailored lifestyle intervention program, over 24 weeks. A substudy of immunologic and metabolic biomarkers is ongoing. The primary endpoint of METABOLyx is PASI90 response at week 24. Other endpoints include patient-reported outcomes and safety. METABOLyx represents the first large scale clinical trial of an immunomodulatory biologic in combination with a standardized lifestyle intervention.