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Pooled review (meta-analysis)

Pooled review of 56 studies of sweeteners in adults and children found mixed results

Toews and colleagues · BMJ (Clinical research ed.) · 2019

Original title: Association between intake of non-sugar sweeteners and health outcomes: systematic review and meta-analyses of randomised and non-randomised controlled trials and observational studies.

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What the study found

Mixed

In adults, sweeteners were linked to lower BMI (mean difference -0.6, 95% CI -1.19 to -0.01; two studies, n=174). In children, BMI z score rose less than with sugar (-0.15, -0.17 to -0.12). Most other outcomes showed no difference.

The study at a glance

Type of study
Pooled review (meta-analysis)
Who or what was studied
56 studies · healthy adults and children, with or without overweight, in 56 studies (35 observational)
What was tested
Sweetener use compared with no use, lower use or sugar
What it measured
The question itself: body weight and metabolic health
Who has a stake
No stake declared
Supported by WHO. No financial ties to groups with an interest in the work.
Journal
BMJ (Clinical research ed.), 2019
Source
PubMed record 30602577. This page is based on the abstract only.

How much this study counts

  • ✓Pools the results of 56 studies.
  • •A pooled review is only as strong as the studies it pools.
  • ✓Measured the question itself: body weight and metabolic health.
  • ✓No competing interests declared.
  • •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: body weight

    4

    1 benefit, 1 mixed, 2 no difference

  2. Trials in people: other measures

    0

    None among the papers we read.

  3. Trials in people: lab tests or safety

    7

    1 benefit, 1 mixed, 4 no difference, 1 harm

  4. Population studies

    5

    1 benefit, 4 harm

  5. Blood levels and genes

    1

    1 harm

↓ Weaker evidence

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

How it fits with the other research

The short answer to “Do artificial sweeteners cause weight gain?”

Trials say no; population studies disagree.

Confidence: low. Based on 32 on-topic papers.

Read the full answer
  • Part of the finding “Against sugar, sweeteners mostly meant less gain”.
  • Summed up in “What reviews found”: Pooled 56 studies, 35 of them observational. Very low to low certainty evidence showed a small BMI drop in adults (-0.6, two studies, n=174) and less BMI z score gain in children versus sugar. Most outcomes showed no difference.
  • Marked as a key paper in the research timeline: WHO-supported review finds few clear effects.

Other reviews on this question

See all 32 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 two reads differed. The reviewer checked the abstract and kept the first read. 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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