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Pooled review (meta-analysis)

Pooled review of 23 studies: highest ultra-processed food intake linked to higher death risk

Pagliai and colleagues · The British journal of nutrition · 2021

Original title: Consumption of ultra-processed foods and health status: a systematic review and meta-analysis.

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 harm

Highest intake was linked to more all cause death (RR 1·25), heart disease (RR 1·29), stroke (RR 1·34), depression (RR 1·20), and overweight or obesity (+39 %).

The study at a glance

Type of study
Pooled review (meta-analysis)
Who or what was studied
23 studies, 183,491 people · Adults in 23 studies; 183,491 people followed 3.5 to 19 years in the cohort studies
What was tested
Highest vs lowest ultra-processed food intake
What it measured
The question itself: death, heart disease, diabetes and cancer
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
The British journal of nutrition, 2021
Source
PubMed record 32792031. This page is based on the abstract only.

How much this study counts

  • ✓Pools the results of 23 studies with 183,491 people.
  • •A pooled review is only as strong as the studies it pools.
  • ✓Measured the question itself: death, heart disease, diabetes and cancer.
  • •The PubMed record has no conflict-of-interest statement.
  • •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 pooled review (meta-analysis), and reviews and opinion pieces discuss studies that are already counted on the steps below.

↑ Stronger evidence

  1. Trials in people: death and chronic disease

    2

    1 no difference, 1 harm

  2. Trials in people: other measures

    3

    1 mixed, 1 no direction, 1 harm

  3. Trials in people: lab tests or safety

    1

    1 mixed

  4. Population studies

    17

    1 mixed, 16 harm

  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 “Are ultra-processed foods bad for your health?”

Linked to worse health; cause not proven.

Confidence: low. Based on 38 on-topic papers.

Read the full answer
  • Summed up in “What reviews found”: Combined twenty-three studies, with cohorts of 183 491 people followed 3·5 to 19 years. Highest intake was linked to more death from any cause (risk ratio 1·25) and heart and blood vessel disease (risk ratio 1·29), though in few studies.
  • Open item for a person: Reviews Lane 2024, Dai 2024, Barbaresko 2025 and Pagliai 2021 pool many of the same cohorts; their agreement is not fully independent.
  • Open item for a person: No COI statement in PubMed for several relevant papers, including Hamano 2024, Pagliai 2021, Barbaresko 2025, Meine 2024 and Hang 2023.

Other reviews on this question

See all 38 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 1 field 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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