The invention relates to medicine and can be used when excessive weight in patients needs to be reduced. The technical result consists in effectively reducing excessive weight by completely excluding the possibility of taking in solid food and reducing food addiction, while not harming the teeth and soft tissues. The technical result is achieved in that, in a method for reducing excessive weight, which comprises reducing the caloric intake, carrying out feeding only with liquid food, and providing passive fixation between the upper and lower jaw by means of an intraoral fixing device using a polymeric adhesive material on 4-7 teeth, allowing a gap of 0.75-1.5 cm between the jaws, which rules out the possibility of chewing food, according to the invention the passive fixation of the jaws is carried out using an intraoral device according to claim 2 which is arranged and fixed in the mouth cavity on either the upper jaw or the lower jaw. The intraoral device is in the form of a right and a left element corresponding to the shape of the upper and lower sections of a patient's jaw, the device having recesses corresponding to the right and left side of the upper and lower jaw, and vertical flanges on the internal and external side, allowing a gap of 0.75-1.5 cm between the jaws, and according to the invention the device has through openings in a horizontal plane.L'invention concerne la médecine et peut être utilisée lors d'une diminution nécessaire de l'excédent de poids chez des patients. Le résultat technique consiste en une diminution efficace de l'ecxédent de poids grâce à l'empêchement total d'absorption de nourriture solide, une diminution de la dépendance alimentaire sans traumatiser les dents ni les tissus mous. Ce résultat technique est atteint grâce à un procédé de diminution d'excédent de poids qui consiste à réduire l'alimentation calorique, à assurer une alimentation uniquement avec de la nourriture liquide, et à fixer passivement entre elles les mâchoires s
