Conjugated Linoleic Acid (CLA) for Weight Loss
Conjugated linoleic acid (CLA) produces, at best, a tiny and clinically meaningless reduction in body weight and fat, and major regulators and physician groups do not endorse it for weight loss. It is not a worthwhile weight-loss supplement.
Why this grade7-layer evidence engine
Three meta-analyses agree on the same disappointing picture: a statistically detectable but trivially small effect. Whigham 2007 (PMID 17490954) pooled 18 trials and found fat loss of roughly 0.09 kg per week. Onakpoya 2012 (PMID 21990002) reported weight down only 0.70 kg and fat down 1.33 kg after six-plus months. Namazi 2018 (PMID 29672124) found weight down 0.52 kg, fat down 0.61 kg, and BMI down 0.23. The later authors explicitly called these effects not clinically relevant or considerable.
Regulators and clinicians line up against a weight-loss role. The EU's EFSA rejected CLA's body-fat claims, reasoning that fat loss paired with rising lipid-peroxidation and inflammation markers is not a beneficial effect. The US FDA recognizes CLA only as safe in foods and authorizes no weight-loss claim, while the WHO now treats CLA as a trans fat to keep below 1% of calories. The AAFP states plainly that no human data support CLA in weight-loss products.
That combination earns the D counter-evidence, disputed grade. The single positive signal is a small BMI dip, but that isolated surrogate does not equal real fat loss, and safety caveats, including the t10,c12 isomer's link to insulin resistance and a few liver-toxicity case reports, reinforce a do-not-recommend conclusion. Diet, exercise, and structured behavioral programs remain the evidence-based options.
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 = 0.52
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (2 篇 > 0 negative)
- tier_strict_requirement_check — | C→D 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 1 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status