The present invention relates to compositions and foodstuffs for use in increasing gastrointestinal microbiota diversity comprising: a) glucomannan； b) chromium； and c) a prebiotic (FOS). The compositions and foodstuffs are particularly suited for that increasing gastrointestinal microbiota diversity over a prolonged period of time which can assist individuals in reducing their weight and, more importantly, maintaining their lower weight over the longer term.
