EXERT-BCN: an Exercise and Nutrition Regimen to Designed to Improve Body Composition After Treatment for Breast Cancer

Excess adipose tissue is a risk factor for the diagnosis of breast cancer and is also associated with an increased risk of disease recurrence.1 Additionally weight gain during and after treatment for breast cancer is associated with a higher risk of recurrence, distant metastases, and death.2 More specifically, low muscle mass and increased adipose tissue is associated with poorer outcomes after the treatment of breast cancer.3 Yet, most women gain significant weight during and after breast cancer treatment, potentially compromising outcomes. Effective methods to promote weight loss and improve metabolic and hormonal dysregulation, inflammation, and body composition in the breast cancer setting are urgently needed. In the noncancer setting, the promotion of high-quality diets that avoided processed food and simple carbohydrates in the DIETFITS study promoted weight loss4. However, this dietary strategy and others were utilized to result in weight loss, but do not necessarily consider maximizing body composition, i.e., muscle mass preservation or increase, and adipose tissue loss. The major, and some would consider only, non-pharmacological method to increase muscle mass is via resistance training with an adequate stimulus and quantity to elicit and promote hypertrophy.5 Our group has already shown that profound muscle hypertrophy is attainable in a population of women undergoing treatment for breast cancer, particularly when the dose threshold of load and repetitions is met. At interim analysis, this program revealed a 2 lb. increase in muscle mass and a 6 lb. decrease in adipose tissue after a 3 month program utilizing linear progression. Based on the DIEFITS protocol which has been described as a "healthy low-carbohydrate" diet, participants will be advised to eat nutrient dense food sources high in vitamins, minerals, and nutrients. Participants will be told to limit processed foods, sugar, bread, pasta, and other simple carbohydrates. Participants will be advised to eat plenty of colorful and nonstarchy vegetables. Finally, participants will be told to avoid snacking between meals, cook most/all meals, eat with family and friends, avoid eating food in the car or on the run, and focus on whole foods that require preparation. This protocol resulted in significant weight loss at one year. Additionally, the lack of calculations and quantification of calories leaves this as a more user-friendly option for participants. The exercise regimen from EXERT-BC has yet to be combined with a dietary intervention. Thus, the following protocol will assess our resistance training regimen in conjunction with a nutrition intervention similar to the DIETFITS Protocol. This will allow adequate assessment of whether we can optimize body composition in these individuals with both exercise and dietary changes.