The present invention provides a composition of dietary fiber supplements for satiety enhancement and appetite suppression in treatment of overweight, obesity, or eating disorders. The composition of the dietary fiber supplements consist of at least one cationic polymer and at least one anionic polymer. The cationic polymers and the anionic polymers in the composition can be dissolved or dispersed in an aqueous solution. When the pH of the aqueous solution is lowered, such as the solution is ingested into the stomach with a gastric pH environment or the aqueous solution is added with some acidifying agents, the aqueous solution will turn into a gel. The formation of a gel from the aqueous solution after it being ingested into the stomach before a meal would provide a satiety enhancement and appetite suppression effect.