The present invention provides a mechanical device for stimulating stomach muscles, comprising a belt-like element sized to be worn with a section thereof adjacent the stomach muscles of the wearer, the belt being associated with a motor and a power element for driving the motor, the motor being mechanically linked to means for intermittently tensioning at least the section to repeatedly intermittently press against the stomach muscles of the wearer in order to stimulate the muscles to contract as a reaction and in anticipation of the repeated intermittent contact.