Lifestyle Intervention for the Reduction of Breast Cancer Risk in Normal Weight Women

PRIMARY OBJECTIVE: I. Evaluate the feasibility of a diet and exercise intervention to decrease body fat in postmenopausal women with normal body mass index (BMI) but high body fat (trunk fat mass 9.4 kg, the 50th percentile of normal BMI women in the Women's Health Initiative \[WHI\]). SECONDARY OBJECTIVE: I. Assess preliminary efficacy of the intervention by evaluating the post-intervention differences between the intervention and control groups in: IIa. Circulating markers of inflammation and metabolic dysfunction linked to both excess adiposity and breast cancer (high sensitivity C-reactive protein \[hsCRP\], fasting insulin, leptin, IL-6, triglycerides, sex hormone binding globulin \[SHBG\], adiponectin, and high density lipoprotein \[HDL\] cholesterol). IIb. Body composition body fat, trunk fat mass, fat mass, lean mass, fat-free mass). EXPLORATORY OBJECTIVE: I. Exploratory outcomes include fitness (oxygen consumption VO2 peak, sit-to-stand test), behavior (physical activity, energy intake, macronutrient consumption), and quality of life (global health-related quality of life, physical functioning, sleep, menopausal symptoms). OUTLINE: Participants are randomized to 1 of 2 groups. GROUP I: Participants complete lifestyle intervention consisting of 1-3 sets of high-resistance circuit training sessions per week, up to 150 minutes of aerobic training per week, and diet recommendations from a health coach or registered dietitian twice per week for 16 weeks. GROUP II: Participants are placed on a wait-list and then complete lifestyle intervention after 4 months.