A s we progress into the 21 st century, the landscape of research and treatment in type 1 diabetes (T1D) is undergoing a massive transformation, characterized by rapid advances on numerous scientific fronts, including insulin and other hormonal therapies, technologies for blood glucose (BG) monitoring and insulin delivery, stem cell therapies, genetic engineering, b-cell transplantation, and even xenotransplantation. Clearly, these scientific advances have enormous implications for future diabetes management. These rapid developments and cutting-edge discoveries may also have important, but not always obvious, implications for our perspectives on how different aspects of diabetes management should be prioritized in research and patient care. For example, with the enthusiasm generated by recent technological breakthroughs, especially those associated with closed-loop control (CLC) or the artificial pancreas (AP), is there a reason to be concerned that more traditional (and perhaps less ''exciting'') aspects of T1D management, such as lifestyle modifications, will receive less attention in research and diabetes care? How relevant are lifestyle factors, including diet and exercise, to contemporary views and practice of T1D treatment? What role will they play in future diabetes management? This column explores the potential impact of recent scientific advances on attitudes regarding the importance of lifestyle modification in T1D treatment, as well as the possibility that there is a growing tendency to undervalue their role as essential determinants of clinical outcome.For both T1D and type 2 diabetes (T2D), lifestyle modification has always been, and remains, one of the most formidable tasks in diabetes management. It is somewhat surprising that there is evidence that dietary as well as physical activity habits are actually poorer in both youth and adults with T1D than their peers without diabetes.1-5 For this reason, it is appealing to envision a future in which technology, such as CLC systems, would offer a solution to the problem of lifestyle modification. The primary goal of automated glucose control is, of course, to benefit T1D individuals (and someday those with T2D) by improving glycemic status and medical outcome.6 Just as important, these systems have the potential to greatly improve quality of life by reducing the psychological and behavioral burden of diabetes management. Among the many burdens that living with T1D imposes, the demands of lifestyle modifications, especially the constant monitoring and/or regulation of food intake, have significant negative effects on quality of life. With CLC systems, patients with T1D can imagine being able to eat whatever and whenever they want, and engage in as much or as little exercise as they desire, all while maintaining BG levels in a safe and healthy range. However, it is important to recognize the extent to which this automated model of glucose control radically changes the traditional paradigm of self-management of T1D, in which patient decision-making and be...