Randomised controlled trialindependent cross-checkabstract checked I-UPF-124 standard review
Ultra-processed vs unprocessed meals of the same calories
Effect of ultra-processed-rich versus ultra-processed-free preload meals at high and low energy density on ad libitum energy intake: a randomized crossover trial.
Overview
Barros LM et al.. Appetite 2026 · PMID 42633852 · DOI 10.1016/j.appet.2026.108761
When people ate fixed portions, ultra-processed meals did not make them eat more at the next meal.
Does the study support the specific claim? No · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
To separate processing from energy density.
- How was the study done?
Randomised crossover trial.
- How many people, animals or samples were studied?
19 young adults.
- What was actually found?
No effect of processing on later intake.
- How large was the observed effect?
-24.5 kcal (-87 to 38).
- What do the results mean in everyday life?
Calorie density and eating speed may matter more than processing.
- What are the study's limitations?
Tiny, one-day.
- What does it say about Elawady's specific claim?
Limits C-UPF-02.
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
Cannot show UPF diets do not cause overeating over days.
Scientific in-depth review
1. Full reference
- Authors
- Barros LM et al.
- Journal
- Appetite
- Year
- 2026
- Identifier
- PMID 42633852 DOI 10.1016/j.appet.2026.108761
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
COI statement in record: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
2. Research question
Do UPF-rich vs UPF-free preload meals at high vs low energy density affect later ad libitum intake?
3. Study design and population
- Study design
- Randomised controlled trial – Randomised 2x2 crossover trial (processing x energy density of preload meals)
- Population
Healthy young adults
- Country
Not stated in abstract
- Period
Not stated
- Sample size
19
- Inclusion and exclusion criteria
Adults; mean age 22.1, BMI 23.5
4. Methods and endpoints
- Exposure / intervention
Preloads with >=80% energy from UPF; high energy density (>=2.0 kcal/g)
- Comparator
0% UPF; low energy density (<=1.2 kcal/g)
- Endpoints
Ad libitum dinner energy intake vs control day; appetite ratings
- Statistical methods
Mixed-effects linear models
5. Actual results
- Results
No main or interaction effects on dinner energy intake: UPF -24.5 kcal (-87 to 38); energy density -41.6 kcal (-104 to 20.9). High energy density slightly increased hunger and reduced fullness; processing did not affect short-term satiety.
- Absolute risks
Not applicable
- Authors' conclusion
Food processing did not affect short-term satiety; acute energy-density differences produced small appetite changes without affecting subsequent intake.
6. Strengths
- Factorial design separating processing and energy density
7. Weaknesses
- 19 participants; single-day conditions
- Fixed preloads (not ad libitum all day)
8. Risk of bias
- Orienting tool
- RoB 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Small, short.
9. Assessment of the statistical interpretation
CIs exclude large effects (>90 kcal) at a single meal.
10. Relevance to the specific claim
When energy is fixed, processing per se did not change later intake at one meal - limits the mechanism in C-UPF-02.
11. Independent contrary findings
Ad libitum all-day trials (Hall, Hamano) show larger effects.
12. Transferability to Germany and Europe
Moderate.
13. Overall methodological judgement
Short-term limiting evidence.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | not replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Longer factorial trials.
15. Linked fact checks
- Ultra-processed foods drive overeating and weight gain: in an NIH randomized trial, people ate about 500 kcal more per day and gained 0.9 kg in two weeks on an ultra-processed diet. – Studies contradicting or limiting the claim