Is weight gain preventable in women with early breast cancer undergoing chemotherapy? A real-world study on dietary pattern, physical activity, and body weight before and after chemotherapy

PURPOSE: We aimed to investigate the role of a lifestyle intervention and clinical and therapeutic factors for preventing weight gain in early breast cancer (BC) patients from one week before to 12 months after chemotherapy. METHODS: Dietary assessments were conducted by a trained dietician using a food-frequency questionnaire at each clinical assessment. Total energy, macronutrients intakes, and physical activity were estimated and the Mediterranean Diet Score (MDS) for adherence to Mediterranean diet was calculated. At each follow-up visit, patients were provided with dietary advices according to Mediterranean and Italian guidelines by a registered dietician, after evaluation of their food records. The associations of clinical characteristics, dietary pattern, and physical activity with weight gain were evaluated by multiple logistic regression, with weight gain ≥5% from baseline value as a dichotomous dependent variable. RESULTS: 169 early BC patients who met all follow-up visits and provided complete data were included in the analysis. From baseline to last assessment, weight loss (≥5% decrease from baseline value), stable weight, and weight gain were observed in 23.1%, 58%, and 18.9% women, respectively. Overall, a 0.68 kg mean decrease in women’s weight (−1.1% from baseline) was observed. The risk of gaining weight increased for having normal weight/underweight at baseline, receiving hormone therapy, MDS worsening, and physical activity decreasing from baseline to last assessment. CONCLUSION: Providing simple suggestions on Mediterranean diet principles was effective for preventing weight gain in normal weight women and favoring weight loss in overweight and obese women. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10549-023-07095-8.