Background: Excess adiposity has been shown to be associated with increased risk for breast cancer recurrence, and a plant-based eating pattern has been hypothesized to be protective. Whether a plant-based diet without specific energy goals will result in weight loss or changes in body composition in women who have been diagnosed with breast cancer has not been fully explored.
Aim of the study: This study was conducted to identify changes in body weight, anthropometric measures, and body composition over a four year period in a sub-sample of breast cancer survivors participating in a dietary intervention targeting increased intake of vegetables, fruit and fiber and decreased dietary fat intake.
Methods: This randomized, controlled dietary intervention study compared longitudinal changes in intakes, body weight, waist:hip ratio (WHR), body mass index (BMI) and body composition by treatment group among fifty-two women previously treated for Stage I, II, or IIIA breast cancer from the Arizona site of the Women's Healthy Eating and Living Study. The dietary intervention aimed for eight servings of fruit and vegetables, 30 g fiber, < or = 20% total energy from fat per day, as well as daily intake of vegetable juice. The comparison group was advised to follow general dietary guidelines for cancer prevention.
Results: The dietary intervention resulted in a significant and sustained increase in fiber, fruit, vegetable, and vegetable juice consumption (p < 0.05) among intervention group subjects as compared to comparison group subjects. The first 6 months resulted in a reduction in body weight and body fat among the intervention group subjects while the comparison group subjects remained stable. Subsequent measurements, at 12, 24 or 36, and 48 months, showed no significant differences in mean body weight, BMI, WHR, or body composition by study group. Also, no significant changes in these measures were demonstrated for either study group between baseline and 48 months.
Conclusions: The dietary intervention efforts resulted in significant changes in diet toward an increase in plant foods and a decrease in dietary fat. Changes in weight, WHR, BMI, and body composition were not different over time or by study group assignment. Interventions that promote a plant-based diet without specific energy restriction do not appear to promote changes in body weight or body composition in women who have been diagnosed with breast cancer. To adequately examine the role of energy restriction in reducing obesity-associated breast cancer recurrence, future interventions should include prescribed energy imbalance either through reduced intake and/or increased expenditure.