Plain language summary

Excess caloric intake and poor nutritional quality are associated with overweight and obesity. A traditional Mediterranean diet has been shown to reduce all-cause mortality, and in particular to reduce risk of cardiovascular disease, type 2 diabetes mellitus and overweight. The aim of this randomised, prospective, single-blinded study was to evaluate the effectiveness of an intensive lifestyle intervention programme in 6874 overweight or obese men and women with metabolic syndrome in Spain. The intervention group was advised on an energy-reduced Mediterranean diet and exercise and received behavioural support, with initial group sessions and interviews, and monthly follow-up phone calls for one year. The control group received advice on a Mediterranean diet and usual care, with 6 monthly follow-ups. After 12 months, the more intensively counselled patients showed a significantly better adherence to an energy-reduced Mediterranean diet than the control group. They had greater reductions in refined grains, pastries, red and processed meats and greater increases in vegetable, fruit and nut consumption than the control group. The intervention group had also better improvements in cardiovascular risk factors.


Importance: High-quality dietary patterns may help prevent chronic disease, but limited data exist from randomized trials about the effects of nutritional and behavioral interventions on dietary changes. Objective: To assess the effect of a nutritional and physical activity education program on dietary quality. Design, Setting, and Participants: Preliminary exploratory interim analysis of an ongoing randomized trial. In 23 research centers in Spain, 6874 men and women aged 55 to 75 years with metabolic syndrome and no cardiovascular disease were enrolled in the trial between September 2013 and December 2016, with final data collection in March 2019. Interventions: Participants were randomized to an intervention group that encouraged an energy-reduced Mediterranean diet, promoted physical activity, and provided behavioral support (n = 3406) or to a control group that encouraged an energy-unrestricted Mediterranean diet (n = 3468). All participants received allotments of extra-virgin olive oil (1 L/mo) and nuts (125 g/mo) for free. Main Outcomes and Measures: The primary outcome was 12-month change in adherence based on the energy-reduced Mediterranean diet (er-MedDiet) score (range, 0-17; higher scores indicate greater adherence; minimal clinically important difference, 1 point). Results: Among 6874 randomized participants (mean [SD] age, 65.0 [4.9] years; 3406 [52%] men), 6583 (96%) completed the 12-month follow-up and were included in the main analysis. The mean (SD) er-MedDiet score was 8.5 (2.6) at baseline and 13.2 (2.7) at 12 months in the intervention group (increase, 4.7 [95% CI, 4.6-4.8]) and 8.6 (2.7) at baseline and 11.1 (2.8) at 12 months in the control group (increase, 2.5 [95% CI, 2.3-2.6]) (between-group difference, 2.2 [95% CI, 2.1-2.4]; P < .001). Conclusions and Relevance: In this preliminary analysis of an ongoing trial, an intervention that encouraged an energy-reduced Mediterranean diet and physical activity, compared with advice to follow an energy-unrestricted Mediterranean diet, resulted in a significantly greater increase in diet adherence after 12 months. Further evaluation of long-term cardiovascular effects is needed. Trial Registration: Identifier: ISRCTN89898870.

Lifestyle medicine

Fundamental Clinical Imbalances : Hormonal
Patient Centred Factors : Mediators/Weight loss/metabolic syndrome
Environmental Inputs : Diet ; Nutrients ; Physical exercise
Personal Lifestyle Factors : Nutrition ; Exercise and movement
Functional Laboratory Testing : Blood

Methodological quality

Jadad score : 3
Allocation concealment : Yes