Dietary energy density and appetite: A systematic review and meta-analysis of clinical trials.

Studies have suggested that dietary energy density (DED) may affect weight gain by altering appetite. Although many studies have investigated the effect of DED on appetite, findings are inconsistent and, to our knowledge, there are no systematic reviews and meta-analyses on this topic. Therefore, the aim of this systematic review and meta-analysis was to summarize the effect of DED on appetite. The current meta-analysis revealed changing the DED had no significant effect on hunger but increased fullness. More high-quality randomized controlled trials are needed to investigate the effects of DED on appetite components. We searched titles, abstracts, and keywords of articles indexed in ScienceDirect, MEDLINE, and Google Scholar databases up to July 2018 to identify eligible RCT studies. Random effects model was used to estimate the pooled effect of DED on appetite. Among the 21 studies identified in the systematic literature search, 11 reports were included in the meta-analysis. Based on the Cochrane Collaboration Risk of Bias tool, 6 studies were considered as good quality, two were fair, and three studies were poor. The mean ± standard deviation for energy density, in studies which assessed fullness, was 1.65 ± 1 in high energy dense (HED) diet and 0.93 ± 0.93 in low energy dense (LED) diet. The corresponding values for hunger were 1.67 ± 0.69 and 0.70 ± 0.32, respectively. Compared with a LED diet, consumption of HED increased fullness (weighed mean difference [WMD] 2.95 mm; 95% CI 0.07-5.82, P = 0.044, I2 98.1%) but had no significant effect on hunger (WMD 1.31 mm; 95% CI -7.20 to 9.82, P = 0.763, I2 99.1%). The current meta-analysis revealed changing the DED had no significant effect on hunger but increased fullness. More high-quality RCTs are needed to investigate the effects of DED on appetite components.