Background <p>The aging of the global population exacerbates the burden of gastrointestinal diseases in elderly individuals. The Developmental Origins of Health and Disease (DOHaD) hypothesis suggests that early-life malnutrition may have long-lasting effects on adult health. However, evidence regarding the link between childhood famine exposure and the risk of gastrointestinal diseases in old individuals remains limited.</p> Methods <p>We conducted a retrospective cohort study of 4227 participants from the China Health and Retirement Longitudinal Study (CHARLS). Childhood famine exposure was defined as experiencing hunger before age 18 during the 1959–1961 famine period. The outcomes were doctor-diagnosed gastric or other digestive diseases. Logistic regression, propensity score matching (PSM), subgroup analysis, and XGBoost machine learning with SHAP explanation were used.</p> Results <p>A total of 83.7% of the participants had childhood famine exposure. The famine-exposed group had a significantly higher risk of gastrointestinal diseases (OR = 1.34, 95% CI: 1.12–1.61); this association persisted after PSM (OR = 1.39, 95% CI: 1.10–1.75). Subgroup analysis yielded consistent results (all P values for interactions &gt; 0.05). Famine exposure was identified as an important predictive factor in the XGBoost machine learning algorithm.</p> Conclusions <p>Childhood famine exposure is significantly associated with an increased risk of gastrointestinal diseases in old individuals. This simple indicator should be included in regular health assessments for the elderly to facilitate early identification and intervention for high-risk populations.</p>