Consumption of fast foods and ultra-processed foods and breast cancer risk: a systematic review and meta-analysis

Abstract

Background: The increasing consumption of fast foods (FFs) and ultra-processed foods (UPFs) worldwide has raised concerns due to their association with carcinogenic compounds and potential links to various cancers. However, this evidence about breast cancer risk remains inconsistent. This study aimed to meta-analyze the association between FFs and UPFs consumption and the risk of breast cancer in females.

Methods: A comprehensive search on online databases was conducted from inception to May 2025, and relevant study data were extracted. The meta-analysis utilized odds ratio (OR) with 95% confidence interval (CI) as effect size measures. Subgroup analyses, heterogeneity assessment, publication bias, and sensitivity analyses were performed to ensure robustness. All statistical analyses were conducted using STATA.

Results: The pooled analysis of 17 observational studies showed a significant association between the highest FFs and UPFs consumption and increased breast cancer risk (OR 1.25, 95% CI [1.09-1.43], p = 0.001). Subgroup analysis revealed a significant positive association between FFs and UPFs consumption and breast cancer risk in case-control studies, but not in cohort studies or menopausal status and a significant association was observed in studies with sample sizes > 1000 and < 1000. Furthermore, the association was significant in Latin America when BMI adjustment was considered for 'yes' and 'no'.

Conclusions: This meta-analysis identified a significant association between the consumption of FFs and UPFs and an increased risk of breast cancer, with high intake linked to a 25% greater risk. These findings suggest that diets high in UPFs may play a role in breast cancer development. As UPF consumption continues to rise, public health strategies and regulatory policies targeting food processing, marketing, labeling, and accessibility are essential for cancer risk reduction and prevention.

Keywords: Breast cancer; Epidemiology; Fast food; Nutrition; Processed food; Risk.

Fig. 1

PRISMA Flow chart of the study selection process in the systematic review

Fig. 2

Forest plot detailing the effect size (ES) with 95% confidence intervals (CI) for the association between the highest vs. lowest fast foods (FFs) and ultra-processed foods (UPFs) intake and the risk of breast cancer in adult women

Fig. 3

Forest plot detailing the effect size (ES) with 95% confidence intervals (CI) of the subgroup analysis based on the study design for the association between the highest vs. lowest fast foods (FFs) and ultra-processed foods (UPFs) intake and the risk of breast cancer in postmenopausal women

Fig. 4

Forest plot detailing the effect size (ES) with 95% confidence intervals (CI) for the association between the highest vs. lowest fast foods (FFs) and ultra-processed foods (UPFs) intake and the risk of breast cancer in A premenopausal and B postmenopausal women

Fig. 5

Forest plot detailing the effect size (ES) with 95% confidence intervals (CI) of the subgroup analysis based on the sample size for the association between the highest vs. lowest fast foods (FFs) and ultra-processed foods (UPFs) intake and the risk of breast cancer in women

Fig. 6

Forest plot detailing the effect size (ES) with 95% confidence intervals (CI) of the subgroup analysis based on the study location for the association between the highest vs. lowest fast foods (FFs) and ultra-processed foods (UPFs) intake and the risk of breast cancer in adult women

Fig. 7

Forest plot detailing the effect size (ES) with 95% confidence intervals (CI) of the subgroup analysis based on the body mass index (BMI) for the association between the highest vs. lowest fast foods (FFs) and ultra-processed foods (UPFs) intake and the risk of breast cancer in adult women

Fig. 8

Funnel plot of publication bias with 95% confidence limits