Importance The benefits of fluid and sodium restriction in patients hospitalized with acute decompensated heart failure (ADHF) are unclear. Objective To compare the effects of a fluid-restricted (maximum fluid intake, 800 mL/d) and sodium-restricted (maximum dietary intake, 800 mg/d) diet (intervention group [IG]) vs a diet with no such restrictions (control group [CG]) on weight loss and clinical stability during a 3-day period in patients hospitalized with ADHF.