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

Inclusion Criteria: * Age 50-69 years old * Postmenopausal woman (absence of menstruation for at least one year, or history of bilateral oophorectomy) * Self-reported height and weight indicating a BMI \>= 18.5 and \< 25 kg/m\^2 * No contraindications to exercise (either no positive responses on the Physical Activity Readiness Questionnaire, or clearance from a health care provider certifying that the participant is healthy enough to exercise) * No history of invasive cancer, other than non-melanoma skin cancer * No history of renal disease * Able to walk without an assistive device * Not within 3 months of major surgery * Able to speak/read/write in English * Has internet access on a computer or mobile device * A trunk fat mass \>= 9.4 kg as indicated by a dual x-ray absorptiometry (DXA) scan * Height and weight indicating a BMI of \>= 18.5 and \< 25 kg/m\^2 verified at the screening visit Exclusion Criteria: * MD Anderson employees that report to the principal investigator of this study * Participants that cannot engage in the exercise program for more than three weeks during the study period * Participants that are currently doing strength exercises that work all major muscle groups (defined as: participants who complete more than 16 repetitions per exercise in their current resistance training regimen, or who don't find their last 1-2 reps to be difficult in their current regimen, or who increase the weight in their current routine).