Women with prior gestational diabetes mellitus (GDM) are encouraged to adopt healthy lifestyle behaviours to prevent or delay type 2 diabetes. The objective was to examine the association between the adoption of preventive practices and the metabolic profile of women with prior GDM. Analyses included 181 women who had GDM between 2003 and 2010. The preventive practices examined included (i) regular physical activity (≥150 min·week(-1)) assessed with the International Physical Activity Questionnaire; (ii) a healthy diet (score derived from the Alternate Healthy Eating Index and associated with a lower metabolic risk) evaluated from a food frequency questionnaire; and (iii) exclusive breastfeeding (≥6 months). Women were classified according to the number of preventive practices adopted. Waist circumference, weight, and height were measured and body mass index (BMI) was calculated. Fasting insulinemia and glycemia were obtained and Matsuda index for insulin sensitivity was calculated. Nearly one-third of women adopted none of the listed preventive practices. For each increase of 1 preventive practice adopted, women were 30% less likely to have a BMI ≥ 25 kg·m(-2) (odds ratio (OR): 0.70, 95% confidence interval (CI) (0.50-0.98)), they were 34% less likely to have a waist circumference ≥ 88 cm (OR: 0.66, 95%CI (0.47-0.92)) and they were 33% less likely to have a Matsuda index for insulin sensitivity < 9.69 (OR: 0.67, 95%CI (0.48-0.94)). These results suggest that women with prior GDM who adopt the recommended preventive practices in the years following delivery are less likely to have lower insulin sensitivity, less likely to be overweight-obese, and less likely to be characterized by abdominal obesity.