Endometrial cancer is the most prevalent gynecological malignancy in developed countries including Europe and the United States [1], and occurs in middle-aged and elderly women in the perimenopausal period [2]. However, it affects approximately 7% of young women (aged 20–44 years) [3], and a trend towards younger age at incidence has been observed in recent years [4]. Traditional hysterectomy deprives young women of the chances of pregnancy and childbirth; this causes considerable distress to individuals and families. Fertility preservation has therefore become the focus of attention in the treatment of endometrial cancer and various societies and groups have published guidelines or consensus statements on fertility-sparing treatment for endometrial cancer [[5], [6], [7], [8], [9]].

Obesity is recognized as a major risk factor for the development of endometrial cancer [10]. Notably, several retrospective studies have shown that obesity reduces complete remission and pregnancy rates and increases recurrence rates in patients with endometrial cancer and atypical hyperplasia who undergo fertility-sparing treatment [[11], [12], [13]]. Guidelines or consensus statements for fertility-sparing treatment in endometrial cancer recommend weight management. However, prospective intervention studies on the effectiveness of systematic weight management models in patients receiving reproductive function-preserving treatment for endometrial cancer and atypical hyperplasia are lacking. This study therefore aimed to investigate the impact of the DEAR weight management model on body morphology and composition, glycolipid metabolism, and tumor outcomes in overweight and obese patients with endometrial cancer and atypical hyperplasia who underwent reproductive function-preserving treatments.