Bone, Exercise, Alendronate, and Caloric Restriction

The purpose of this research is to identify strategies that minimize bone loss that occurs when older adults lose weight. Participation in this research will involve up to nine assessment visits and last up to two years.

Inclusion Criteria: * Community-dwelling * BMI\>30 kg/m\^2 or BMI 25.0 to \-2.5 at the hip, femoral neck, or lumbar spine (L1-L4)) Exclusion Criteria: * Weight greater than 450 lbs (DXA limit) * Resides with someone who is currently participating in BEACON * Dependent on quad cane or walker; inability to walk independently * History of mild cognitive impairment or dementia or evidence of cognitive impairment ((score \21 drinks/week) in the past month; any non-cannabis illicit drug use * Weight change ≥5% in past 3 months * Regular participation (\>60 mins per day on \> 3 days/week) in structured strength training program for \>6 months * Severe arthritis, fracture, chronic injury, or other musculoskeletal disorder that prevents safe exercise participation; joint replacement or other orthopedic surgery in past 6 months or planned in next 12 months; invasive dental procedure (i.e. extraction/implant) in past 6 month or planned in next 12 months * Osteoporosis (any of the following): Self-reported and on prescription osteoporosis medication; self-reported prior spine, hip, wrist, or shoulder fracture after age 40 (except when caused by trauma or fall from height), including atypical femoral fractures (AFF); or ≥20% for major osteoporotic fracture at screening * Uncontrolled hypertension (systolic \>180 OR diastolic \>110 mmHg) upon repeated assessments (up to 3 times) * Uncontrolled type 2 diabetes (HbA1c \>8%); dialysis or abnormal kidney function (eGFR \