The food fiber supplement contains 30 to 35 parts by weight protein, 50 to 68 parts by weight insoluble polysaccharides and 2 to 3 parts by weight ash, wherein in the ash are contained 16 to 18 parts by weight phosphorus, 12 to 18 parts by weight calcium, 5 to 15 parts by weight magnesium and 14 to 20 parts by weight potassium.