CONCLUSIONS In otherwise healthy overweight or obese adults , there is some evidence that in the short term GM may help to reduce BW , but not BMI .
OBJECTIVE Glucomannan ( GM ) , a soluble fiber derived from the plant Amorphophallus konjac , is marketed as being helpful in reducing body weight .
However , the data supporting this cl aim are scarce .
The aim of this review was to systematic ally evaluate the effects of GM on body weight ( BW ) and body mass index ( BMI ) in otherwise healthy obese or overweight children and adults .
Effect of glucomannan on obese patients: a clinical study.
An eight-week double-blind trial was conducted to test purified glucomannan fiber as a food supplement in 20 obese subjects .  Glucomannan fiber ( from konjac root ) or placebo was given in 1-g doses ( two 500 mg capsules ) with 8 oz water , 1 h prior to each of three meals per d. Subjects were instructed not to change their eating or exercise patterns . Results showed a significant mean weight loss ( 5.5 lbs ) using glucomannan over an eight-week period . Serum cholesterol and low-density lipoprotein cholesterol were significantly reduced ( 21.7 and 15.0 mg/dl respectively ) in the glucomannan treated group . No adverse reactions to glucomannan were reported
CONCLUSIONS In otherwise healthy overweight or obese adults , there is some evidence that in the short term GM may help to reduce BW , but not BMI .
OBJECTIVE Glucomannan ( GM ) , a soluble fiber derived from the plant Amorphophallus konjac , is marketed as being helpful in reducing body weight .
However , the data supporting this cl aim are scarce .
The aim of this review was to systematic ally evaluate the effects of GM on body weight ( BW ) and body mass index ( BMI ) in otherwise healthy obese or overweight children and adults .