Most studies asked people to remember what they ate over time, which isn’t very accurate—so the real link between leafy greens and diabetes might be even stronger than what was found.
Scientific Claim
Dietary intake was primarily assessed using food frequency questionnaires, which are subject to recall bias and measurement error, potentially underestimating true associations between diet and type 2 diabetes risk.
Original Statement
“Assessment of true dietary intake is inherently difficult, and the use of food frequency questionnaires has been criticised... Such attenuation could have masked an association in our meta-analysis.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The claim accurately reflects the authors’ own critique of measurement tools without overstating the impact. It correctly identifies a known source of bias without implying causation.
Evidence from Studies
Supporting (1)
Fruit and vegetable intake and incidence of type 2 diabetes mellitus: systematic review and meta-analysis
The study used surveys where people remembered what they ate, which can be inaccurate—this might make it harder to see the real link between food and diabetes, supporting the idea that these surveys can miss the true effects.