A weight loss device (1, 100) comprising at least one peripheral plate (10, 20, 110, 120) that can be fixed to at least one portion of an upper dental arch (2) or lower dental arch (3) by fixing means, in a fixing configuration. The peripheral plate (10, 20, 110, 120) supports, by way of supporting means (40, 140), at least one central plate (30, 130), which is adapted, in the fixing configuration, to rest against the palate (4) or the floor of the mouth (5) in order to limit the movements of the tongue (7) inside the mouth (6).