Weight Gain Prevention in Adolescents and Young Adults

Inclusion Criteria: * Age 18 to M 25 at screening * BMI \>/= 25 to \< 30 kg/m\^2 * Family history of obesity defined as one biological parent with severe obesity (BMI \>/= 35) and/or two biological parents with obesity (BMI \>/=30). Parental obesity status will be confirmed by obtaining a release of information to review and electronic health record. Exclusion Criteria: * Tanner stage 1-4 * Diabetes (type 1 or 2) * Current or recent (\<6 months prior to screening) use of anti-obesity medication(s) or other weight-altering medication(s) (e.g. atypical anti-psychotics, attention deficit hyperactivity disorder (ADHD) stimulant) * Previous bariatric surgery * Current or recent (\<6 months prior to screening) use of medication(s) to treat insulin resistance * Recent initiation (\<3 months prior to screening) of anti-hypertensive or lipid medication(s) * History of glaucoma * Current or recent (\<14 days prior to screening) use of monoamine oxidase inhibitor * Known hypersensitivity to sympathomimetic amines * History of treatment with growth hormone * Patient Health Questionnaire-9 (PHQ-9) score of \>/= 15 at screening * Eating disorder symptoms within 6 months and/or any past medical diagnosis of eating disorder * Major psychiatric disorder * Unstable clinically-diagnosed depression * History of suicide attempt * Suicidal ideation of type 4 or 5 on the Columbia-Suicide Severity Rating Scale (C-SSRS) at any time during the study * Current pregnancy or breastfeeding * Plans to become pregnant * If sexually active, refusal to use 2 forms of birth control * Tobacco use * Alanine transaminase (ALT) or aspartate transaminase (AST) \>/= 2.5 times the upper limit of normal * Bicarbonate 18 mmol/L * Creatinine \> 1.2 mg/dL * Creatinine clearance \<50 mL/min (Schwartz formula) * History of seizures * Uncontrolled hypertension * History of structural heart defect * History of clinically significant arrhythmia * Diagnosed monogenic obesity * History of cholelithiasis * History of nephrolithiasis * Hyperthyroidism * Untreated thyroid disorder