Objective Lifestyle intervention to reduce weight can improve glucose control and cardiometabolic risk factor in obese patients with type 2 diabetes, at least, as long as the intervention continues. We aimed to assess the changes of the weight, dietary composition and insulin resistance in obese women with type 2 diabetes after the 12 weeks dietary calorie restriction (12 w) and 1 year follow up of the intervention (1 y). Methods A total 80 patients with type 2 diabetes were randomly assigned to intensive dietary intervention (IDI) group or control group. IDI group were recommended to reduce their usual dietary calorie by -500 kcal/d and provide biweekly individual intervention in 12w. Follow up assessments were performed after 1y. We measured the insulin resistance (IR) by HOMA-IR. Results Of the 80 patients, 82.5% completed the 1y. Weight (-6.6% vs -0.3%, respectively, P < 0.001) and HbA1c showed larger reduction in IDI group than control group at 12w, however, no significant group differences were found in weight and HbA1c regain between 12w and 1y. In the IDI group, initial weight decreased at least 5% in 84.4 % and 63.3 % after 12w and 1y, respectively. IDI group showed larger reduction of carbohydrate intake and IR than control group at 12w, however, there was significant difference between the groups in carbohydrate intake but not in IR after 1y. The decrease of weight for 1y showed positive correlation with the decreased in weight and carbohydrate intake for 12w (r = 0.755, P < 0.001; r = 0.685, P＜0.001, respectively). Conclusion A 12 week intensive dietary calorie restriction can induce significant weight loss (≥ 5%) in obese women with type 2 diabetes and maintain this loss in more than 60% of patients after 1y. The greater initial weight and carbohydrate reductions for 12w were associated with long term weight and carbohydrate intake maintenance.