Abstract: The present invention relates to a waist band of a non-stretchable material intended as an aid to weight reduction and long-term maintenance of a weight reduction and as an aid to preventing fatness in persons of normal weight. The waist band (1) is characterized in that it is provided with a clasp (2) in the form of a one-way lock which only allows tightening of the band (1) around the waist but which does not allow for loosening thereof.