does intermittent fasting decreases the cholesterol
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Here is a thorough, evidence-based answer:
Does Intermittent Fasting Lower Cholesterol?
Yes - but the effect is modest and depends on the type of IF and what is being measured.
What the Evidence Shows
A comprehensive umbrella review in eClinical Medicine (2024) combining 23 meta-analyses found good evidence that intermittent fasting lowers:
- LDL cholesterol (the "bad" kind)
- Total cholesterol
- Triglycerides
- Fasting insulin, systolic blood pressure, waist circumference, and fat mass
A more recent umbrella review (Hua et al., 2025, PMID: 39618023) covering literature up to June 2024 added a specific finding: high-quality evidence supports the 5:2 diet reducing LDL cholesterol. TRE (time-restricted eating) showed strong benefits for weight and insulin but lipid effects were rated moderate-to-low quality evidence.
The most current evidence comes from a network meta-analysis in the BMJ (June 2025, PMID: 40533200) comparing IF strategies head-to-head against each other and against standard diets.
Effects by Lipid Type
| Lipid | Effect of IF | Confidence |
|---|---|---|
| LDL cholesterol | Modest reduction (~5-10 mg/dL) | Moderate-high (especially 5:2 diet) |
| Triglycerides | Reduction, especially with caloric deficit | Moderate |
| Total cholesterol | Modest reduction | Moderate |
| HDL cholesterol | Variable; slight increase with some protocols | Low-moderate |
How Does It Work?
The main mechanisms are:
- Metabolic switching - during fasting, the liver breaks down triglycerides into fatty acids and ketone bodies. This reduces circulating triglycerides and LDL.
- PPAR-alpha and PGC-1a activation - these signals in the liver increase fatty acid oxidation and raise ApoA (which increases HDL), while decreasing ApoB (which lowers LDL).
- SREBP-2 modulation - intermittent fasting suppresses this sterol regulatory protein, reducing cholesterol synthesis in the liver.
- Caloric deficit - much of the benefit may actually be driven by eating less overall rather than the fasting timing per se.
Which IF Protocol Works Best for Cholesterol?
- 5:2 diet (eat normally 5 days, ~500-600 kcal on 2 days): strongest evidence for LDL reduction
- Alternate-day fasting (ADF): inconsistent effects; some trials show benefit, others do not
- Time-restricted eating (TRE / 16:8): modest triglyceride reduction, limited consistent effect on LDL or HDL
- Ramadan fasting: modest improvements in triglycerides and HDL
Important Caveats
- Most of the cholesterol benefit disappears when IF is compared to continuous caloric restriction with the same calorie reduction - suggesting the timing of fasting may matter less than just eating less overall.
- A controversial 2024 AHA observational study suggested 8-hour TRE was associated with higher cardiovascular mortality, but it had major methodological limitations (2-day self-reported data, no peer review at release). No causal link has been established. The British Heart Foundation advised against drawing firm conclusions from it.
- Effects are generally more pronounced in overweight/obese individuals and those with metabolic syndrome or type 2 diabetes.
- Short follow-up durations in most trials (weeks to months) limit conclusions about long-term cardiovascular benefit.
Bottom Line
Intermittent fasting produces modest, real improvements in cholesterol - particularly LDL and triglycerides - mostly driven by the 5:2 protocol and alternate-day fasting. The effects are comparable to caloric restriction, and much of the benefit may stem from eating fewer calories overall. IF is a reasonable dietary strategy for lipid improvement, especially in overweight individuals, but it is not a substitute for statins in people with established dyslipidemia or high cardiovascular risk.
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