Associations between dietary energy density and obesity: A systematic review and meta-analysis of observational studies

Objective: Although many studies have shown an association between dietary energy density (DED) and obesity, there has been no systematic review and meta-analysis on this topic. Therefore, the objective of this study was to qualitatively and quantitatively review and summarize the literature on association between DED and obesity. Methods: We searched titles, abstracts, and keywords of articles indexed in ScienceDirect, ProQuest, MEDLINE, and Google Scholar databases until January 2015 to identify eligible studies. We excluded studies that did not examine DED for whole diet and studies that included patients with cancer, pregnant women, the elderly (>60 y old), and children (<2 y old). There were no language or publication date restrictions. Results: Of the 37 studies included in this review, most articles reported a direct association between DED and obesity. We performed a meta-analysis on 23 of these studies. In comparison with the lowest NTILE of DED, subjects in the highest NTILE of DED had significant weight gain (2.26 kg, 95% confidence interval [CI]: 1.00-3.53), greater adjusted mean body mass index (BMI) (0.50 kg/m(2), 95% CI: 0.02-0.98 for males and 0.85 kg/m(2), 95% CI: 0.51-1.19 for females), and risk of excess adiposity (odds ratio [OR]: 1.27, 95% CI: 1.04-1.55). We did not observe significant associations between DED and risk of elevated BMI (OR: 1.13, 95% CI: 1.00-1.27) and abdominal obesity (OR: 1.17, 95% CI: 0.19-7.38). We found no evidence of publication bias. Conclusion: The present review showed that DED was directly associated with risk of excess adiposity, higher weight change, and BMI. Lower DED should be considered a prevention strategy for obesity. (C) 2016 Elsevier Inc. All rights reserved.