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Systematic review

Review of 130 trials: some fasting plans linked to benefit, mostly weak evidence

Patikorn and colleagues · JAMA network open · 2021

Original title: Intermittent Fasting and Obesity-Related Health Outcomes: An Umbrella Review of Meta-analyses of Randomized Clinical Trials.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

Points to benefit

Of 104 links, 28 (27%) showed benefit, mostly weak evidence. One link with high-quality evidence: modified alternate-day fasting for 1 to 2 months lowered BMI vs regular diet. Fasting was also linked to less fat-free mass.

The study at a glance

Type of study
Systematic review
Who or what was studied
130 studies · adults, including those with overweight or obesity
What was tested
alternate day fasting, 5:2 diet and time restricted eating in 130 trials (median follow-up 3 months); comparison groups not stated except regular diet for one link
What it measured
Several kinds of outcomes
Who has a stake
Company stake
One author earns fees for a book on alternate-day fasting; another reported symposium fees.
Journal
JAMA network open, 2021
Source
PubMed record 34919135. This page is based on the abstract only.

How much this study counts

  • •Sums up 130 studies found with a set search method, without pooling the numbers.
  • •Measured several kinds of outcomes.
  • –Company stake: One author earns fees for a book on alternate-day fasting; another reported symposium fees.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

This paper is not on the ladder. It is a systematic review, and reviews and opinion pieces discuss studies that are already counted on the steps below.

↑ Stronger evidence

  1. Trials in people: weight loss

    9

    5 benefit, 2 mixed, 2 no difference

  2. Trials in people: other measures

    8

    4 benefit, 3 mixed, 1 no difference

  3. Trials in people: lab tests or safety

    1

    1 benefit

  4. Population studies

    0

    None among the papers we read.

  5. Blood levels and genes

    0

    None among the papers we read.

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does intermittent fasting help with weight loss?”

Yes, but about like calorie cutting.

Confidence: moderate. Based on 26 on-topic papers.

Read the full answer

Other reviews on this question

See all 26 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The reviewer corrected 2 fields after reading the abstract. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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