[Olive Oil and Body Weight. Systematic Review and Meta-Analysis of Randomized Controlled Trials].

Background: Olive oil, as fundamental fat in the Mediterranean diet, has contributed to a decrease in obesity in several epidemiological studies. It is unknown whether olive oil itself can decrease the weight independently of the diet used. The objective of this work was to determine the efficacy of olive oil in reducing weight.
Methods: Systematic review of meta-analysis of randomized controlled trials (RCTs) of at least 12 weeks of intervention on adults without previous cardiovascular events to estimate the effect of an olive-enriched diet on weight, waist and body mass index. The search was performed in PubMed, Embase, Cochrane plus, Web of Science, Ovid, Scopus, Virtual Health Library (BVS), Theses and Dissertations Online (TDX) until December 2016. No language, gender or underlying pathology was restricted. We used Stata14 SE for data synthesis.
Results: 490 studies were identified, of which only 11 studies met the inclusion criteria. A diet enriched in olive oil reduced weight more than control diet: -0.92 kg, 95% CI (-1.16, -0.67), p heterogeneity = 0.1; decreased waist circumference in -0.60 cm, 95% CI (-1.17, -0.04), p heterogeneity = 0.6; and diminished BMI in -0.90, 95% CI (-0.91, -0.88), p heterogeneity < 0.001. The benefits were seen when olive oil was supplemented in its natural state and not when capsules were given.
Conclusions: A diet enriched with olive oil can be an important weight control strategy in people without previous cardiovascular events.