Meta-analysisindependent cross-checkabstract checked★ key study I-WHT-115 in-depth review

Trials found whole grains do not change body weight or waist

Whole-Grain Consumption Does Not Affect Obesity Measures: An Updated Systematic Review and Meta-analysis of Randomized Clinical Trials.

Overview

Sadeghi O et al.. Adv Nutr 2020 · PMID 31390462 · DOI 10.1093/advances/nmz076

In 21 randomised trials, eating whole instead of refined grains did not change weight, BMI, waist or fat mass.

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

Study explained simply

What did the researchers want to find out?: Whole grains and obesity in RCTs.
How was the study done?: Meta-analysis.
How many people, animals or samples were studied?: 1798 adults.
What was actually found?: No effect on obesity measures.
How large was the observed effect?: Waist WMD 0.06 cm.
What do the results mean in everyday life?: Swapping bread type alone does not slim you.
What are the study's limitations?: Short trials; reporting error.
What does it say about Elawady's specific claim?: Contradicts causal claim.
Do the results apply to Germany and Europe?: High.
What can explicitly not be concluded from this study?: Cannot exclude long-term effects.

Authors: Sadeghi O et al.
Journal: Adv Nutr
Year: 2020
Identifier: PMID 31390462 DOI 10.1093/advances/nmz076 · PMC7073321
Verification: verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
Retracted: no
Corrections: Corrigendum published: Adv Nutr 2020;11(2):468 (doi 10.1093/advances/nmz130; PDF-only, content not read).
Extent checked: abstract only
Conflicts of interest and funding: not stated in abstract

Does whole-grain consumption affect obesity measures?

Study design: Meta-analysis – Systematic review and meta-analysis of RCTs
Population: Adults >=18 years in RCTs
Country: International
Period: Searches to February 2019
Sample size: 21 studies, 1798 participants
Inclusion and exclusion criteria: RCTs of whole-grain products/diets vs control

Results: No significant effect on body weight (19 studies), BMI (10 trials), body fat % (WMD 0.27; -0.05 to 0.58), fat mass (0.45; -0.12 to 1.02 kg), fat-free mass (reported as 0.31; -0.67 to 0.06 kg - point estimate outside its CI, probable sign error), waist (0.06; -0.50 to 0.63 cm).
Absolute risks: not reported
Authors' conclusion: Findings do not support whole-grain intake for controlling obesity measures.

Fat-free mass WMD 0.31 lies outside its CI (-0.67 to 0.06); likely -0.31 (stats/C-WHT-06).

Contradicts a causal role of refined vs whole grains in obesity measures in the short term.

I-WHT-114 (long-term cohort association).

High.

Important counter-evidence to causal wording.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
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

Long-term trials.