Meta-analysisindependent cross-checkabstract checked I-SOD-122 standard review
Sugary drinks raise liver fat when they add extra calories
Important Food Sources of Fructose-Containing Sugars and Non-Alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis of Controlled Trials.
Overview
Lee D et al.. Nutrients 2022 · PMID 35889803 · DOI 10.3390/nu14142846
Across 51 trials, fructose-containing sugars raised liver fat only when they added extra calories, most clearly from sugary drinks.
Does the study support the specific claim? Partly · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Assess food sources of fructose and liver fat.
- How was the study done?
Meta-analysis of controlled feeding trials.
- How many people, animals or samples were studied?
2059 participants.
- What was actually found?
Excess calories from sugary drinks raised liver fat; equal-calorie swaps did not.
- How large was the observed effect?
IHCL SMD 1.72 in addition trials.
- What do the results mean in everyday life?
Extra sugary drinks on top of normal food fatten the liver.
- What are the study's limitations?
Short trials; industry links.
- What does it say about Elawady's specific claim?
Partly supports; the effect depends on excess calories.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Cannot show long-term disease.
Scientific in-depth review
1. Full reference
- Authors
- Lee D et al.
- Journal
- Nutrients
- Year
- 2022
- Identifier
- PMID 35889803 DOI 10.3390/nu14142846
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
CIHR and Diabetes Canada (PubMed grants); author disclosures include food-industry links (abstract record)
2. Research question
Do fructose-containing sugars from different food sources affect NAFLD markers at different levels of energy control?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis of controlled trials >=7 days by energy-control design; GRADE
- Population
Predominantly healthy younger adults, mixed weight
- Country
International
- Period
to 7 January 2022
- Sample size
51 trials, 75 comparisons, 2059 participants
- Inclusion and exclusion criteria
Controlled trials >=7 days
4. Methods and endpoints
- Exposure / intervention
Fructose-containing sugars from 10 food sources (SSB, fruit juice, fruit, honey, sweets, etc.)
- Comparator
Control diets by design (substitution, addition, subtraction, ad libitum)
- Endpoints
Intrahepatocellular lipid (IHCL); ALT; AST
- Statistical methods
Random effects; GRADE
5. Actual results
- Results
Total fructose-containing sugars increased IHCL in addition (excess-energy) trials (SMD 1.72, 1.08-2.36) and had no effect in substitution or ad libitum trials. SSBs increased IHCL and ALT in addition trials (high certainty for IHCL; moderate for ALT).
- Absolute risks
not applicable
- Authors' conclusion
Energy control and food source mediate the effect of fructose-containing sugars on NAFLD markers; excess energy from SSBs leads to large increases in liver fat.
6. Strengths
- Large trial base
- Stratified by energy design and food source
- GRADE
7. Weaknesses
- Short trials
- Author industry links
- Surrogate markers
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Abstract-level judgement.
9. Assessment of the statistical interpretation
Effect depends on excess energy; isocaloric exchange shows no effect.
10. Relevance to the specific claim
Mixed for C-SOD-04: supports that SSB with excess calories raise liver fat (high certainty), but contradicts a calorie-independent, soft-drink-specific 'overwhelming' of the liver.
11. Independent contrary findings
Geidl-Flueck 2021 (I-SOD-121) showed lipogenesis increase without energy excess.
12. Transferability to Germany and Europe
Applicable.
13. Overall methodological judgement
Clarifies that dose and energy balance are central.
| 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
Long-term trials with clinical endpoints.