Nutrient intake plays a significant role in the health outcomes of all pregnant women. In a pregnancy complicated by gestational diabetes mellitus (GDM), excellent glucose control is as foundational as appropriate weight gain and adequate nutrient intake. The controversies in GDM management include the following: how far to manipulate energy intake, dietary composition (carbohydrates and fats), and gestational weight gain. Signs that food restrictions have gone too far include weight loss or lack of weight gain, undereating to avoid insulin therapy, positive urinary ketones, and intentional restriction of healthy foods. If a balance between nutrient needs and glucose control cannot be achieved, then concurrent medication therapy is needed to assist in reducing insulin resistance and supplementing insulin production to provide normoglycemia and improved pregnancy outcomes. Medical nutrition therapy is a self-management therapy. Education, support, and follow-up are required to assist the woman to make lifestyle changes essential to successful nutrition therapy. Women with GDM are at increased risk for type 2 diabetes; learning to manage GDM with lifestyle change provides an opportunity to affect personal risk factors and the health of the whole family.