Objective To investigate the relationship between dietary factors and postoperative breast cancer metastasis and to provide a basis for dietary intervention in this population. Methods Based on the breast cancer cohort established in the Breast Cancer Surgery Department of Southwest Medical University Affiliated Hospital in 2013

a case-control study was conducted. The case group consisted of 140 breast cancer patients with metastasis identified during follow-up from January 2013 to December 2018. The control group was matched on age within a range of ±3 years and underwent breast cancer radical surgery within a one-month difference in timing compared to the case group. The surgical procedures

postoperative adjuvant therapy plans

and exclusion criteria（such as patients with preoperative recurrence

metastasis

or concurrent tumors in other organs）were consistent between the two groups. A total of 140 patients who did not experience breast cancer metastasis during the same period were selected as the control group. Pathological data and dietary frequency were compared between the two groups. SPSS 20.0 was used for univariate analysis and multivariate logistic regression analysis to identify independent risk factors associated with postoperative metastasis of breast cancer. Results The results of univariate analysis showed statistically significant differences in the intake of meat

vegetables

and fruits between the metastasis group and the control group（P < 0.001）. The results of multifactorial conditional logistic regression modeling showed that daily consumption of less than the recommended intake of vegetables [OR（95% CI）5.068（1.873-13.716）

P < 0.001]

daily consumption of less than the recommended intake of fruits [OR（95% CI）8.119（2.721-24.228）

P < 0.001] and daily consumption of meat more than the recommended intake [OR（95% CI）5.009（1.847 ~ 13.585）

P < 0.05] were independent risk factors for the development of metastasis in postoperative breast cancer patients. Conclusion Daily consumption of less than the recommended intake of vegetables（< 200 g）and fruits（< 300 g）and daily consumption of more than the recommended intake of meat（> 75 g）were both independent risk factors for postoperative metastasis of breast cancer

which affected the prognosis of patients.