Tailoring Mobile Health Technology to Reduce Obesity and Improve Cardiovascular Health in Resource-Limited Neighborhood Environments

* INCLUSION CRITERIA: Individuals eligible for this protocol are overweight or obese (BMI \>= 25 kg/m\^2) African American women aged 21-75 years who live in Washington, DC Wards 5,7, or 8 and neighboring areas of Prince George s County, MD. Eligible participants should also have access to a smartphone compatible with the mobile app for the protocol that they can use for the study. Eligible participants must be able to provide informed consent independently and also speak and read English at the 8th grade level. EXCLUSION CRITERIA: * Medical condition, including heart failure, recent unintentional weight loss or physical limitation, that might prohibit safe participation in physical activity for any reason * Heart disease as indicated by history of myocardial infarction in past 1 year, documented obstructive coronary artery disease on coronary angiography, coronary artery stent placement, within the last year significant structural heart disease (e.g. hypertrophic or dilated cardiomyopathy with EF \<35%, severe valvular heart disease) with evidence of decompensation. * Pregnant women due to large hormonal changes during pregnancy that affect study variables and potential pregnancy-related restrictions on exercise. All participants of childbearing potential will need to self-report a negative pregnancy at the screening visit, baseline visit, and at the three-month and six-month visits, unless the participant self-reports being postmenopausal, having had a tubal ligation, or having undergone a complete hysterectomy. Pilot Study INCLUSION CRITERIA: * Must be an African-American female * Must be within the age of 21-75 years old * Must be overweight or obese (Body Mass Index (BMI) \>= 25 kg/m\^2) * Must live in Washington DC Wards (5, 7, or 8) or live in Prince George s County, Maryland * Must have a smartphone that is compatible with the study software (mobile app) * Must be willing to use the software on personal smartphone for the study * Must be able to provide consent * Must be willing to wear the wrist-worn physical activity device for the study * Must not be pregnant Optional MRI Tests Subjects will be screened for implanted metal objects or devices that may be incompatible with MRI (i.e. cerebral aneurysm clip, cochlear implant, pacemaker, etc.) These subjects will be eligible to proceed with study enrollment, but will not undergo the optional MRI study.