Objective: To assess the influence of a Mediterranean dietary pattern (MeDiet) on anthropometric and body composition parameters in one of the centers of the PREDIMED randomized dietary trial.
Subjects/settings: 351 Canarian free-living subjects aged 55 to 80 years, with type 2 diabetes or ≥3 cardiovascular risk factors.
Intervention: Participants were randomly assigned to one of 3 different dietary interventions: MeDiet + extra-virgin olive oil (EVOO), MeDiet + nuts (walnuts, almonds, and hazelnuts), or a control low-fat diet. Total energy intake was ad libitum.
Outcome measures: Measures included changes in anthropometric measures (weight, body mass index [BMI] and waist circumference [WC]), body fat distribution, energy, and nutrient intake after 1 year. Body composition (percentage of total body fat [%TBF], total fat mass [TFM], free fat mass [FFM], percentage of truncal fat [%TrF], truncal fat mass [TrFM]) and total body water (TBW) were estimated by octapolar electrical impedance analysis.
Statistical analyses: Paired t tests were conducted to assess within-group changes. Analyses of variance (ANOVAs) were used to assess the effect of the dietary intervention on the percentage change in anthropometric variables, body composition, and dietary intake profile. All pairwise comparisons that were statistically significant in ANOVA were subsequently adjusted using the Benjamini-Hochberg test, which penalizes for multiple comparisons.
Results: After 1 year of intervention, significant within-group reductions in all anthropometric variables were observed for the MeDiet + EVOO and the control group. The MeDiet + nuts group exhibited a significant reduction in WC and TBW. The control group showed a significant increase in %TBF and a reduction in TBW. The control group showed a significant increase in the percentage of total body fat and a reduction in TBW. However, we did not find any between-group significant difference in anthropometric or body composition changes.
Conclusions: Mediterranean diets enriched with EVOO or specific mixed nuts (walnuts, almonds, hazelnuts) that contain approximately 40% total fat can be alternative options to low-fat diets for weight maintenance regimes in older overweight or obese adults.
Keywords: Mediterranean diet; PREDIMED Study; body composition; body fat; obesity; octapolar bioimpedance analysis.