Effects of Whole Grain, Compared to Refined Grain, Intake on Subjective Measures of Appetite: A Systematic Review and Meta-Analysis

Abstract

Abstract Objectives Results from observational studies indicate that whole grain intake is inversely associated with BMI and risk of weight gain. Whole grain intake may influence energy balance and body composition through effects on appetite and thus, energy intake. To evaluate the impact of whole grain food consumption on appetite, we performed a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing whole grain food intake and subjective measures of appetite in adults. Methods A search of PubMed, Scopus and Food Science and Technology abstracts yielded 34 RCTs measuring hunger ratings after consuming whole grain foods compared to refined grain controls. Seventeen of these studies (598 subjects), with a total of 33 unique whole grain treatments, reported areas under the curve (AUC) for subjective hunger and were included in the meta-analysis. Pooled estimates from meta-analyses are expressed as standardized mean differences (SMD). Results Intake of whole grain foods resulted in significantly lower subjective hunger AUC (range for AUC times ranged from 120 to 270 min) compared to refined grain foods [SMD −0.36, P < 0.001, 95% CI (−0.48, −0.24)]. Sensitivity analyses were also completed in which studies with AUC values for < and ≥ 180 min were evaluated separately, as well as hunger ratings at the 180 min timepoint alone, and the results were similar to those for the main analysis (SMDs −0.33 to −0.54, all P ≤ 0.03). Conclusions These results support the view that consumption of whole grain foods, compared to refined grain controls, significantly reduces subjective hunger, and this may provide at least part of the explanation for the inverse associations between whole grain food intake and risks for overweight, obesity and weight gain over time. Funding Sources This study was funded by the Bell Institute of Health and Nutrition, General Mills, Minneapolis, MN and registered with PROSPERO.