Diabetes and obesity have each become a national health crisis in recent years. The number of people who have diabetes and prediabetes continues to grow with a predicted number of 336 million people worldwide with type 2 diabetes by 2030. The prevalence of diabetes has risen in parallel with the increased prevalence of obesity. The optimal nutrition therapy for the treatment of both diabetes and obesity remains controversial. Health care practitioners are no longer solely prescribing the conventional low-fat, higher-carbohydrate diet approach that was used for over a decade. Lower-carbohydrate, higher-fat, or higher-protein diets are now being viewed as equally or sometimes more effective treatment plans for diabetes and obesity. In addition, there are other aspects of diet beyond macronutrient composition that are currently being investigated. This article will summarize research conducted over the past 2 years examining medical nutrition therapy for diabetes and obesity. It will also describe the unique challenges that come with treating this patient population.