This chapter is about managing patients with diagnosed diabetes mellitus while also encouraging a nutrition program that not only controls blood sugar but also is consistent with addressing overweight and obesity-related comorbidities, including age-related chronic diseases. Nutrition is central to the prevention and treatment of diabetes mellitus, but the confusing array of medications and the focus on glucose control have blinded the primary care practitioner to the benefits of weight management interventions for type 2 diabetes (T2DM), which are wrongly thought to be a futile exercise.