This literature review of clinical and preclinical studies aimed to analyse the latest evidence on the Mediterranean diet (MD) and intermittent fasting (IF) to prevent or delay strategies for the onset of cancer in patients with hereditary cancer syndromes, correlating the data about some nutritional, clinical biochemical, and inflammatory biomarkers (e.g. CRP, IL-6, insulin, and IGF-1). The gene discussed is CRP; the disease is Inherited cancer-predisposing syndrome.