Fiber na abinci na waken soya galibi yana nufin kalmar gabaɗaya don yawan sukarin kwayoyin halitta a cikin waken soya waɗanda enzymes ɗin narkewar ɗan adam ba zai iya narkewa ba.Ya ƙunshi cellulose, pectin, xylan, mannose, da dai sauransu. Duk da cewa fiber na abinci ba zai iya samar da kowane nau'in sinadirai ga jikin ɗan adam ba, yana iya daidaita matakin sukarin jini na jikin ɗan adam cikin aminci, hana maƙarƙashiya, da kuma ƙara gamsuwa.