Systematic reviewindependent cross-checkfull text checked★ key study I-SUG-02 in-depth review

Sugar and health: umbrella review

Dietary sugar consumption and health: umbrella review.

Overview

Huang Y et al.. BMJ 2023 · PMID 37019448 · DOI 10.1136/bmj-2022-071609

Across 73 meta-analyses, high sugar intake was linked to 45 adverse outcomes; authors advise under 25 g/day of added sugar.

Does the study support the specific claim? No · Methodological quality: high

Original publication

Plain-language summary

Study explained simply

What did the researchers want to find out?: Quality and validity of evidence on sugar and health outcomes.
How was the study done?: Umbrella review of 73 meta-analyses.
How many people, animals or samples were studied?: 73 meta-analyses; 83 outcomes; Humans free of acute/chronic disease
What was actually found?: Significant harmful associations with 45 outcomes; moderate-quality: SSB and body weight, added sugars and ectopic fat; low-quality: +4% gout per SSB serving/week, +17% CHD and +4% all-cause mortality per 250 mL/day SSB; recommends free/added sugars <25 g/day and SSB <1 serving/week.
How large was the observed effect?: CHD +17% per 250 mL/d SSB
What do the results mean in everyday life?: High sugar intake is more harmful than beneficial.
What are the study's limitations?: Most evidence is observational and of low certainty, and concerns sugary drinks rather than sugar in foods; sucrose intake was even linked to slightly lower diabetes risk in some cohorts; recommendations go beyond the strength of the evidence.
What does it say about Elawady's specific claim?: Supports C-SOD-01/03/05; contradicts C-SUG-01.
Do the results apply to Germany and Europe?: High.
What can explicitly not be concluded from this study?: It cannot show that sugar in any form or small amount is harmful, nor precise effect sizes; it does not cover honey, fruit or sugars eaten in solid foods well.

Scientific in-depth review

1. Full reference

Authors: Huang Y et al.
Journal: BMJ
Year: 2023
Identifier: PMID 37019448 DOI 10.1136/bmj-2022-071609
Verification: verified – PubMed efetch 2026-10-25
Retracted: no
Corrections: none
Extent checked: full text
Conflicts of interest and funding: Funded by the National Natural Science Foundation of China (82000721) and Sichuan Province Department of Science and Technology (2020YJ0054); funders had no role. ICMJE: no relevant financial relationships.

2. Research question

Quality and validity of evidence on sugar and health outcomes.

3. Study design and population

Study design: Systematic review – Umbrella review (PROSPERO CRD42022300982) of 73 meta-analyses (67 of observational studies, 6 of RCTs) with re-analysis where possible, original AMSTAR, GRADE and evidence classes (I, II, III, IV, NS).
Population: Humans free of acute or chronic disease (children and adults)
Country: Multinational
Period: Databases searched from inception to January 2022
Sample size: 73 meta-analyses; 83 unique outcomes (74 observational, 9 RCT); 58 of the 73 concerned sugar-sweetened beverages
Inclusion and exclusion criteria: SR/MA of RCTs, cohort, case-control or cross-sectional studies on total sugars, sugar components or SSB/sugary foods; excluded non-nutritive sweeteners/ASB, short-term supplementation, disease populations, RCTs with isoenergetic replacement of sugars, foods without extractable sugar data (e.g. honey, chocolate, 100% juice), non-English studies; most recent/largest meta-analysis retained per exposure-outcome pair.

4. Methods and endpoints

Exposure / intervention: Dietary sugar consumption (mostly SSB; also fructose, sucrose, added, free and total sugars)
Comparator: Lower consumption
Endpoints: 83 health outcomes
Statistical methods: Random/fixed-effects re-analysis, I2, Egger test (23% of outcomes), AMSTAR, GRADE, evidence classes

5. Actual results

Results: 45 significant harmful and 4 beneficial associations among 83 outcomes; no outcome reached high-quality GRADE or class I evidence. Moderate quality: SSB and body weight in RCTs (WMD 0.85 kg, 0.50-1.20; class IV); added sugars and liver fat (SMD 0.93) and muscle fat (SMD 0.63) (class IV). Low quality: per 250 mL/day SSB, coronary heart disease RR 1.17 (1.11-1.23; class II) and all-cause mortality HR 1.04 (1.02-1.06; class III); per 1 serving/day SSB, type 2 diabetes RR 1.27 (1.15-1.41); highest vs lowest SSB gout RR 1.35 (1.18-1.55); per 25 g/day fructose pancreatic cancer +22% (class III). Beneficial/inverse: sucrose per 25 g/day and type 2 diabetes RR 0.92 (0.85-0.99); sucrose and CVD mortality (inverse). Not associated: added sugar and CVD mortality; fructose and uric acid, body weight, T2D; many cancer sites. Publication bias detected for several outcomes (e.g. T2D, overall cancer, hypertension). Median AMSTAR score 8 (range 3-11).
Absolute risks: not reported in full text
Authors' conclusion: High dietary sugar consumption is generally more harmful than beneficial for health, especially in cardiometabolic disease; the authors recommend free/added sugars <25 g/day and SSB <1 serving/week (approximately 200-355 mL/week).

6. Strengths

Pre-registered; comprehensive search; duplicate selection (kappa 0.906) and extraction
Covers 83 outcomes; RCT and observational evidence separated
Three appraisal frameworks; reports null and inverse associations

7. Weaknesses

Evidence dominated by SSB (58/73 meta-analyses); few data on solid sugars, honey or sugars in foods
Mostly observational; nearly all outcomes low or very low quality; no class I evidence
Excluded isoenergetic-replacement RCTs, so effects may reflect excess energy rather than sugar per se
Original AMSTAR (not AMSTAR 2); English only
Most recent meta-analysis per outcome retained; overlap of primary studies
Recommendations (<25 g/day; <1 SSB/week) go beyond the graded evidence
Internal inconsistency: gout dose-response reported for SSB in the abstract but for artificially sweetened beverages in the results text

8. Risk of bias

Orienting tool: AMSTAR 2 (umbrella review), ROBIS-oriented
Type of assessment: structured assessment based on the full text by a single reviewer (no formal double review)
Full formal assessment: no
Overall risk of bias: some concerns
Rationale: Changed from low: well-conducted review, but English-only search, partial publication-bias assessment and recommendations stronger than the graded evidence. Structured single-reviewer judgement; a complete formal AMSTAR 2/ROBIS assessment requires two independent reviewers.

8. Risk of bias
Domain	Judgement	Rationale
Item 2 (critical) protocol registered	low	PROSPERO CRD42022300982.
Item 4 (critical) comprehensive search	some concerns	Four databases plus reference lists; restricted to English.
Items 5-6 duplicate selection and extraction	low	Two independent reviewers with third-author arbitration.
Item 7 (critical) excluded studies justified	some concerns	Flowchart with reasons; study-level list not visible in main text.
Item 9 (critical) risk of bias assessment	some concerns	AMSTAR (original) for included meta-analyses and GRADE; primary-study confounding not appraised directly.
Item 11 (critical) appropriate synthesis	some concerns	Re-analysis where data allowed; heterogeneous exposure metrics; some outcomes from single meta-analyses.
Item 13 (critical) risk of bias considered in interpretation	some concerns	GRADE low/very low acknowledged, yet firm intake recommendations are made.
Item 15 (critical) publication bias	some concerns	Egger test possible for only 23% of outcomes; bias detected in several.
Item 16 conflicts of interest	low	Public funding; no relevant COI.

Full-text review (25 October 2026): Headline results confirmed. Added: search to January 2022, PROSPERO, 58/73 meta-analyses on SSB, exclusion of isoenergetic RCTs and English-only restriction, no high-quality/class I outcome, inverse sucrose associations (T2D RR 0.92), gout RR 1.35 (not a doubling), T2D RR 1.27 per serving, publication bias findings, funding/COI, internal gout inconsistency (SSB vs ASB). AMSTAR 2 overall changed from low to some_concerns.

9. Assessment of the statistical interpretation

Many modest associations, nearly all low or very low certainty; the most robust findings concern SSB and weight gain/ectopic fat. Sugar in solid form (sucrose) was not consistently harmful and showed some inverse associations, which limits generalising SSB results to all sugar. Overlap with other reviews (e.g. dental outcomes come from A-SOD-19).

10. Relevance to the specific claim

Supports C-SOD-01/03/05; contradicts C-SUG-01.

11. Independent contrary findings

None.

12. Transferability to Germany and Europe

High.

13. Overall methodological judgement

Comprehensive overview supporting harm from high sugar intake, mainly via sugar-sweetened beverages and cardiometabolic outcomes; certainty mostly low; does not show that every form or amount of sugar is harmful.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	high
Risk of bias	some concerns
Precision of results	moderate
Directness	direct
Reproducibility	replicated
Consistency with the overall evidence	consistent
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable

14. Open questions

Causality for many outcomes.

15. Linked fact checks

Regular consumption of sugar-sweetened soft drinks increases the risk of type 2 diabetes (and metabolic syndrome); one to two cans per day raise type 2 diabetes risk by about 26%, and each daily serving by about 18%. – Studies supporting the claim
Sugar-sweetened soft drinks raise the risk of coronary heart disease, cardiovascular death and early death (e.g., two or more daily servings: +35% coronary heart disease in women; +31% cardiovascular and +21% total mortality). – Studies supporting the claim
Two sugary sodas a day double the risk of gout in men. – Studies supporting the claim
White sugar is the greatest product humans ever made; any amount of sugar per day is beneficial, and one can eat a kilogram of white sugar or honey. – Studies contradicting or limiting the claim