Frequent Dining Out Linked to Higher Colorectal Cancer Risk

Regularly eating meals away from home may carry more than just financial costs. A large cohort study of over 42,000 adults in China found that frequent dining out was significantly associated with an increased risk of colorectal cancer.¹ The findings suggest a dose-response relationship, with obesity emerging as a key factor that may partially mediate the link between dining habits and cancer risk.

This cohort study is published in Frontiers in Oncology.

“Our findings indicated that over half of the Chinese adult population reported dining out at least once per week,” wrote the researchers of the study. “Furthermore, a significant association was observed between frequent dining out and an elevated risk of both colon and rectal cancers when compared to individuals who dined out rarely or never.”

Obesity is a well-established risk factor for colorectal cancer, though the impact of body weight changes over time remains less clear.² In a nationwide cohort study of over 3.8 million participants, those who remained obese between 2005 and 2009 had a higher risk of developing colorectal cancer compared with consistently non-obese individuals (HR, 1.08; 95% CI, 1.06-1.11). The risk was particularly pronounced in men, who showed an elevated likelihood of colon cancer (HR, 1.13; 95% CI, 1.10-1.17).

The current study aimed to investigate the relationship between dining out frequency and the risk of developing colon and rectal cancers.¹ Researchers analyzed data from 42,286 adults aged 20 to 60 years who underwent health examinations at 5 major public hospitals in Zibo, Shandong Province, China, between 2010 and 2022.

The team assessed how often participants dined out and their subsequent cancer risk, in addition to exploring potential dose-response relationships. Furthermore, subgroup and sensitivity analyses were performed to verify the robustness of the results and account for possible confounding factors.

During a median follow-up of 10.3 years, the study identified 272 new cases of colon cancer and 181 cases of rectal cancer. After adjusting for potential confounders, researchers found that frequent dining out was significantly associated with an increased risk of both cancers.

Specifically, individuals who dined out often had a 2.23-fold higher risk of developing colon cancer (HR, 2.231; 95% CI, 1.656-3.007) and a 1.79-fold higher risk of developing rectal cancer (HR, 1.793; 95% CI, 1.231-2.611) compared with those who rarely or never dined out. The analysis also revealed a significant non-linear dose-response relationship between dining out frequency and cancer incidence, suggesting that risk rises sharply with more frequent dining out. Furthermore, obesity was found to partially mediate these associations, indicating that body weight may play an important role in the pathway linking dining habits to cancer risk.

However, the researchers acknowledged that several limitations should be noted. First, dining out frequency was self-reported, which may have introduced recall bias. Second, although many covariates were adjusted for, unmeasured confounders may still have been present. Third, the lack of detailed data on meal quantity or type limited the assessment of dose effects. Lastly, although dining habits remained consistent over time, the study included only employed adults under 60, which may have limited generalizability to other populations.

Despite these limitations, the researchers believe the study finds a strong association between frequent dining out and the risk of rectal and colon cancer among this patient population.

“In conclusion, the findings of our study demonstrate that frequent dining out is significantly associated with an elevated risk of colorectal cancer,” wrote the researchers. “Additionally, obesity may partially mediate this relationship. Therefore, it is crucial to implement policies and initiatives aimed at monitoring and addressing these unhealthy lifestyle habits to safeguard public health.”

References

1. Zhang P, Xing WJ, Zhang J, et al. Impact of dining out frequency on the risk of colorectal cancer: insights from a large Chinese cohort. Front Oncol. 2025;15:1626303. doi:10.3389/fonc.2025.1626303

2. Seo JY, Jin EH, Chung GE, et al. The risk of colorectal cancer according to obesity status at four-year intervals: a nationwide population-based cohort study. Sci Rep. https://doi.org/10.1038/s41598-023-36111-6