Objective: The study evaluated the impact of a doctor's or a health professional's instructions on lifestyle behaviors among the US adult diabetic population. Methods: The study population was adult diabetic subjects in the latest National Health and Nutrition Examination Survey (NHANES) 2005 - 2006. Multivariate logistic regression was employed adjusting for the survey design using STATA software. A total of 459 diabetic subjects aged 18 and over were enrolled, which represented about 15 million US adults with diabetes. The three dichotomous categorical independent variables of interest were whether the subject had been told by their doctor or health professional in the last year to lower their risk of certain diseases by controlling weight, by increasing physical activity, or by reducing fat or calorie intake. The outcomes of interest were whether action was currently being taken by the subject to follow that past advice. Results: After controlling potential confounders (including demographics, education, and disease severity), it was found that subjects who were told by their doctor or health professional to lose weight were more likely to be working on weight control, compared with those not told to do so (p<0.001). Similar results were found for exercise advice (p=0.001) and diet advice (p=0.002). This cross-sectional analysis cannot confirm causality and recall bias cannot be eliminated. Conclusion: The study suggests that advice by a doctor or a health professional has great impact on diabetic patients to take actions in changing their lifestyle behaviors.