A body weight management device includes a body weight obtainment unit that obtains measurement data in which a body weight measurement value and a measurement day/time are associated with each other, an increase/decrease amount calculation unit that calculates a target intra-day variation amount by which the body weight varies during sleep, a target obtainment unit that calculates a target value when measuring a pre-sleep body weight value at a second timing before the measurement subject sleeps relative to a post-waking body weight value that is measured at a first timing after the measurement subject wakes, an advice obtainment unit that obtains advice information regarding meals to achieve the target value, based on a result of comparing a pre-meal body weight value measured at a third timing prior to a meal with a threshold value, and an output processing unit that outputs the obtained advice information.
