Chemotherapy-associated changes in nutritional status, body composition, biochemical parameters, and physical activity among cancer patients: insights from a prospective cohort study

Background Chemotherapy is often associated with metabolic and functional disorders that may affect treatment outcomes in cancer patients. This study aimed to assess chemotherapy-induced changes in weight, body composition, nutritional status, biochemical parameters, and physical activity levels in Moroccan cancer patients. Methods This prospective cohort study involved 422 cancer patients treated by chemotherapy. Anthropometric measurements and bioelectrical impedance analysis were used to assess weight status and body composition. Nutritional status was evaluated using the Nutritional Risk Index, and biochemical parameters were obtained from the hospital's database. Physical activity levels were assessed by the International Physical Activity Questionnaire. Results After chemotherapy, there were significant reduction in fat-free mass and increase in body fat percentage (P < 0.001). The proportion of patients with moderate/severe malnutrition, sarcopenic obesity, and low muscle mass increased from 34.2%, 29.1%, and 49.1% pre-treatment to 50.0%, 39.3%, and 57.8% post-treatment, respectively. There was a significant decrease in total protein levels ( P = 0.034). Physical activity and total energy expenditure decreased after chemotherapy (P < 0.001). Younger age (<60 years), low/moderate physical activity levels, and excessive body fat were independently associated with weight gain. Short disease duration (<12 months) and normal nutritional status were protective against moderate/severe weight loss, while non-excessive body fat increased such weight alteration. Non-malnourished patients and those without excess body fat had higher odds for low muscle mass. Conclusions Chemotherapy induced significant alterations in weight, nutritional status, body composition, and physical activity. Early implementation of nutritional and lifestyle interventions is needed in oncological care to prevent treatment-related malnutrition and adverse outcomes in cancer patients.