⭐⭐⭐⭐⭐GLUCOMANNAN FIBRE SHAKE – HIGH FIBRE BOWEL & WEIGHT SUPPORT. ????WHY CHOOSE GLUCOMANNAN FIBRE SHAKE?. Insoluble fibre absorbs water in the large intestine. Glucomannan, when taken as part of anenergy-restricted diet, contributes toweight loss by promoting a feeling of fullness.