Diets · Metabolic & Cardiometabolic
intermittent fasting decreases insulin resistance
Part of: 🥗 intermittent fasting
📅 Last reviewed: 2026-07-15 ⓘ
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: All trials, pooled (Meta-analysis)
How the studies fall
What the evidence shows
Intermittent fasting reduces insulin resistance (and weight/glucose) in PCOS.
The evidence (12)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Siles-Guerrero 2024 2024 · Nutrients | meta-analysis | supports | moderate | fasting NOT superior to continuous calorie restriction; benefit is the deficit |
| Xu L et al 2026 · study_type: animal | animal | supports | moderate | 20h fast/4h feed IF x84d, overweight cynomolgus monkeys n=8/grp; insulin resistance reduced day126 p=0.0004, sustained after refeeding |
| Abu Suilik H et al 2026 · study_type: meta-analysis | meta-analysis | supports | moderate | Network MA, 19 RCTs n=1149 MASLD; ADF only regimen to significantly improve HOMA-IR (direction not fully quantified in abstract) |
| Lu 2025 2025 · J Health Popul Nutr | meta-analysis | supports | high | GRADE MA: IF favorable on IR/inflammation in MetS but controversial, limited certainty |
| Li H et al 2026 · study_type: meta-analysis | meta-analysis | tested-null | moderate | 9 RCTs n=894 MASLD, IF vs CER; no significant between-group difference in glucose-related indices |
| Caretto A et al 2026 · study_type: observational | observational | supports | low | Narrative review states IF improves IR 'primarily via weight loss and gut microbiota modulation'; no effect-size given |
| Ranneh Y, et al. 2025 · Nutrients | meta-analysis | supports | moderate | Pooled (5 trials): IF reduced HOMA-IR −0.94 (p<0.0001), fasting insulin −3.17 µU/mL, FBG −2.86 mg/dL, weight −4.25 kg, BMI −2.05. |
| MacKewn A et al 2026 · Research Square | RCT | mixed | low | 3-arm pre-post 30d, n=79 (IF-only n=16); combined keto+IF > IF-alone on HbA1c reduction, t(30)=2.141,p=.041; no IF-vs-no-IF control HOMA-IR reported |
| An W et al 2026 · study_type: observational | observational | supports | low | 12wk 5:2 IF+meal-replacement, obese PCOS n=90 (PSM); HOMA-IR decreased significantly, P=0.008 |
| Yuan X, Wang J, Yang S, et al. 2022 · Int J Endocrinol | meta-analysis | supports | moderate | Meta-analysis of intermittent-fasting trials: HOMA-IR -0.31 (95% CI -0.44 to -0.19), fasting glucose -0.15 mmol/L (-0.23 to -0.06), insulin -13.25 uIU (-16.69 to -9.82). CAVEAT: BMI (-0.8 kg/m2), weight (-1.87 kg) and waist (-2.08 cm) all fell too, so the insulin-resistance benefit is plausibly weight-mediated rather than a fasting-specific effect. |
| Jiao M et al 2026 · study_type: meta-analysis | meta-analysis | mixed | moderate | Multilevel MA, 65 RCTs n=3293 adults; EX+IF improved fasting insulin and HOMA-IR vs controls |
| Søndergaard AM et al 2026 · study_type: observational | observational | mixed | low | Mini-review of TRE RCTs/meta-analyses: effects on insulin sensitivity 'generally small, variable, and context dependent' |
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