Diets · Metabolic & Cardiometabolic
Does fasting every other day raise bad cholesterol?
The claim, precisely: alternate-day fasting increases LDL cholesterol
Contested Diets 🔬 Includes disconfirming
RefutedContestedStrong support
consensus score 0.00
Unclear — evidence is mixed; one good year-long trial saw a rise, but pooled reviews found no consistent increase.
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
MechanismIn-vitroAnimalObservationalRCTMeta-analysis
How the studies fall
1 support 1 contradict 0 tested null 1 mixed · 3 sources, 2 independent groups
What the evidence shows
Alternate-day fasting raised LDL cholesterol vs daily calorie restriction at 12 months in one RCT - a possible-harm signal needing corroboration.
The evidence (3)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Varady 2015 2015 · Sci Rep | RCT | contradicts | moderate | ADF decreased total cholesterol, LDL-C and TG with weight loss ⚠️ correction-on-file (Crossref) - kept, corrigendum not retraction |
| Trepanowski JF, et al. (Varady) 2017 · JAMA Intern Med | RCT | supports | moderate | 12-mo RCT: LDL increased in the ADF arm vs daily CR |
| Semnani-Azad 2025 2025 · BMJ | meta-analysis | mixed | high | IF strategies improved cardiometabolic markers; NO consistent LDL increase ⚠️ correction-on-file (Crossref) - kept, corrigendum not retraction |
Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.