The prevalence of diabetes and other pathophysiological conditions has been correlated with the incidence of obesity. A large portion of an adult community in the northwestern United States suffers from excessive weight that has been linked to premature mortality rates and certain forms of diabetes. Excess calories from carbohydrate have been shown to increase weight. Therefore, diets that are modified in carbohydrate and calories may help mitigate weight and obesity comorbidities. This qualitative, single case study's purpose was to explore the methods health care professionals use for teaching adults about controlling weight. Altheide and Johnson's analytic realism theory, in which they describe how the experiences of educators and learners affect the way information is perceived, formed the conceptual framework for this study. An illustrative case study paradigm was used to identify the perceptions of licensed health care practitioners regarding the current adult teaching methods for modifying dietary carbohydrate and excess weight. Using a purposeful sample, data were collected in 2 phases with 5 licensed health care practitioners: Phase 1 entailed an open-ended electronic questionnaire and semistructured telephone interviews with open-ended questions during phase 2. Data were analyzed through coding and aggregation by NVivo and Tosmana software, respectively. The findings indicated that the American Diabetes Association (ADA) plate method was the most effective teaching model for controlling weight and carbohydrate intake. Consequently, the ADA plate method was used to create a professional development program to teach health care educators about nutrition instruction methods for adults. The study contributes to positive social change by enhancing preventive health measures for the local adult population through diet therapy education. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]