Brief Summary: This randomized clinical trial studies a group-based lifestyle intervention or usual care in measuring biomarker levels in participants at high risk for breast cancer. Studying the effects that changes to daily eating and exercise habits can have on the body's hormone levels and the body's ability to activate proteins may help doctors identify interventions for individuals at high risk for breast cancer.

Detailed Description: PRIMARY OBJECTIVES: I. To calculate eligibility rates, participation rates, retention, and adherence within the Diet, Exercise and Estrogen Metabolites (DEEM) study. II. To determine inter- and intra-person variability of the estrogen-deoxyribonucleic acid (DNA) adducts (EDA) biomarkers in participants of the DFS. III. To explore the effects of the intervention on percent adiposity and the EDA ratio at the end of the 3-month intervention and 6-month follow-up. SECONDARY OBJECTIVES: I. To explore the effects of the intervention on the DNA damage repair (DDR) biomarker at 3-months. OUTLINE: Participants are randomized to 1 of 2 arms. ARM I: Participants take part in weekly 2-hour group counseling sessions for 6 months with taper beginning at 3 months. Group sessions include education, group process, and experiential learning on the benefits of physical activity, balanced nutrition, and mindfulness techniques. Participants set goals for changing their dietary habits with the help of a mental health counselor and are also encouraged to exercise 3-4 times per week, including experiential group activities such as brisk walking, yoga, Zumba, and group fitness. ARM II: Participants receive their usual care and are also provided with study materials on healthy diet and exercise at the end of the study. After completion of study, participants are followed up for 3 months.