Glucomannan / Konjac Glucomannan (KGM) for Weight Loss
Despite an EU-authorized health claim, the largest and most rigorous trials show glucomannan produces no clinically meaningful weight loss versus placebo. It is not a dependable weight-loss aid, carries documented choking and gut-obstruction risks, and should not replace diet, exercise, or evidence-based treatment.
Why this grade7-layer evidence engine
The clinical-trial record is split but leans negative. The largest and highest-quality meta-analysis (Onakpoya 2014, 9 RCTs, n=531; PMID 24533610) found no significant effect on body weight (-0.22 kg, not significant), and a systematic review of adults and children (Zalewski 2015; PMID 26059384) concluded there is no clinically meaningful benefit. A pediatric RCT (PMID 8247594) was likewise negative. Only an older fibre meta-analysis (Sood 2008; PMID 18842808, about -0.79 kg) and one small 1984 trial (PMID 6096282) suggested a modest effect, so any real benefit is tiny and inconsistent.
Regulators disagree, which is why this grade is disputed. The EU's EFSA authorized a narrow weight-loss claim at 3 g/day taken with water before meals within a calorie-restricted diet. But the US FDA has approved no such claim and maintains an import alert on konjac mini-cup jellies over choking deaths, while WHO/JECFA judges konjac flour safe only as a food additive, not as a weight-loss therapy.
Clinical sources reinforce caution. Cleveland Clinic's obesity-medicine guidance advises against herbal weight-loss products including glucomannan, citing throat or intestinal blockage from tablets and interference with blood-sugar control; major US obesity societies do not endorse it. Net: at best a marginal, unreliable effect paired with real mechanical and drug-interaction risks, hence a Counter-Evidence (D) rating.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.346
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高階證據未達主導 (0 positive vs 1 negative)，由 raw_score 決定
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 1 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status