Digestive cancers account for a substantial proportion of oncological patients, representing over 20% of cases treated in hospitals, and are generally managed through a multidisciplinary approach that has markedly improved survival outcomes over recent decades. Surgical resection remains the cornerstone of curative treatment, often preceded by neoadjuvant chemotherapy, radiotherapy, or combined modalities. Notably, a significant proportion of patients eligible for abdominal surgery are older adults, with approximately one in three being over 75 years of age. Advances such as Enhanced Recovery After Surgery (ERAS) protocols and the centralization of complex surgical procedures have contributed to better outcomes, including higher rates of radical resections, improved survival, reduced postoperative complications, and shorter hospital stays. While some risk factors are non-modifiable, such as age, sex, tumor stage, comorbidities, and tumor biology, several modifiable factors can be optimized prior to surgery to improve postoperative outcomes. These include smoking cessation, enhancement of aerobic capacity and muscular strength, nutritional optimization, emotional resilience, and correction of anemia or other metabolic derangements. Preoperative exercise, ideally embedded within a multimodal prehabilitation program, is recommended for all patients undergoing major surgery. The neoadjuvant period represents a valuable window to implement trimodal prehabilitation strategies encompassing physical exercise, nutritional support, and psychological interventions, aimed at reducing postoperative complications, shortening hospital length of stay, and improving functional recovery. Physical fitness in this context is multidimensional, encompassing aerobic capacity, muscle strength, and body composition. Aerobic capacity predicts postoperative complications and length of hospital stay, while low muscle strength and sarcopenia are associated with higher morbidity and poorer prognosis. Inspiratory muscle training can further reduce pulmonary complications and accelerate recovery. Nutritional status is a critical determinant of surgical outcomes in gastrointestinal cancer, with malnutrition affecting up to 80% of patients at diagnosis. Comprehensive assessment, including dietary intake, anthropometric measurements, physical examination, and biomarkers such as albumin and transferrin, is essential, and targeted interventions including protein supplementation, pancreatic enzyme replacement, or tailored dietary strategies should be implemented when indicated. Body composition, particularly sarcopenia and cachexia, is closely linked to both nutrition and exercise, and can be assessed through imaging techniques such as DXA, CT, or MRI, or via bioelectrical impedance in research settings, with simpler bedside assessments used in clinical practice. Emotional wellbeing also plays a significant role, as preoperative anxiety and depression can negatively influence recovery, adherence to rehabilitation, and overall quality of life. Psychological support, stress management, and behavioral interventions can improve patient engagement and enhance outcomes. The physiological principles of hormesis and cross-stressor adaptation suggest that controlled exercise can improve resilience to both physical and psychological stressors, including the stress of surgery itself. Additional modifiable factors such as absolute cessation of alcohol and tobacco, glycemic control in diabetic patients, correction of anemia (including iron deficiency), and frailty assessment in older adults are critical components of preoperative optimization. Major abdominal surgery carries substantial risk, including infections, bleeding, and anastomotic complications, which directly impact quality of life and lengthen hospitalization. Evidence from randomized controlled trials indicates that multimodal prehabilitation effectively reduces postoperative complications and shortens hospital stay. However, motivating patients to engage in exercise during neoadjuvant therapy can be challenging due to treatment-related fatigue, nausea, and other side effects. Integrating behavioral theories such as Self-Determination Theory and the Theory of Planned Behavior can enhance intrinsic motivation by fostering autonomy, competence, and relatedness, and addressing attitudes, subjective norms, and perceived behavioral control, ultimately promoting adherence to prehabilitation programs and optimizing postoperative recovery.