Growing evidence suggests that healthcare provider advice may reduce alcohol use, increase physical activity, and improve the adoption of other desirable lifestyle behaviors among patients. However, how brief interventions and other provider–patient interactions can shape the cumulative adoption of multiple modifiable behaviors is less well studied for diabetes prevention and control. Using weighted Internet panel survey data from a large socio-demographically diverse urban population in the United States (n = 1003), the present study describes differences in group characteristics among those who ‘had been ever diagnosed’ with prediabetes/diabetes versus those who had not. It also examines the associations between the cumulative adoption of lifestyle behaviors and each of the following: (a) lifetime prediabetes/diabetes diagnosis; (b) brief lifestyle intervention exposure (i.e., ever received provider encouragement to modify lifestyle behaviors); and (c) recent provider–patient communication about diabetes. There were several group differences among those who ‘had been ever diagnosed’ with prediabetes/diabetes versus those who had not, by age, employment status, health status, nutrition knowledge, blood pressure/hypertension diagnosis, and diabetes-related health behaviors (p < 0.05). Each of the three provider–patient interactions of interest were positively associated with a higher cumulative sum of adopted modifiable lifestyle behaviors for diabetes prevention and management. The results suggest that provider advice/provider–patient interactions of any type can have a salutary impact on whether individuals with prediabetes or type 2 diabetes will engage in recommended lifestyle behavior modifications.