Factors associated with successful dietary changes in an energy-reduced mediterranean diet intervention: a longitudinal analysis in the PREDIMED-Plus trial

Purpose: long-term nutrition trials may fail to respond to their original hypotheses if participants do not comply with the intended dietary intervention. We aimed to identify baseline factors associated with successful dietary changes towards an energy-reduced Mediterranean diet (MedDiet) in the PREDIMED-Plus randomized trial. Methods: longitudinal analysis of 2985 participants (Spanish overweight/obese older adults with metabolic syndrome) randomized to the active intervention arm of the PREDIMED-Plus trial. Dietary changes were assessed with a 17-item energy-reduced MedDiet questionnaire after 6 and 12 months of follow-up. Successful compliance was defined as dietary changes from baseline of ≥ 5 points for participants with baseline scores 3 chronic conditions (OR6-month: 0.65, 95% CI 0.53-0.79; OR12-month: 0.76, 95% CI 0.62-0.93), and suffering depression (OR6-month: 0.80, 95% CI 0.64-0.99; OR12-month: 0.71, 95% CI 0.57-0.88). Conclusion: our results suggested that recruitment of individuals with high perceived self-efficacy to dietary change, and those who initially follow diets relatively richer in fiber may lead to greater changes in nutritional recommendations. Participants with multiple chronic conditions, specifically depression, should receive specific tailored interventions.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The PREDIMED-Plus trial was supported by the European Research Council (advanced research grant 2014–2019, 340918 to MAM-G as PI) and by the official Spanish Institutions for funding scientific biomedical research, CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn) and Instituto de Salud Carlos III (ISCIII), through the Fondo de Investigación en Salud (FIS), which is cofunded by the European Regional Development Fund coordinated by J.S.-S. and J.V., including the following projects: PI13/00673, PI13/00492, PI13/00272, PI13/01123, PI13/00462, PI13/00233, PI13/02184, PI13/00728, PI13/01090, PI13/01056, PI14/01722, PI14/00636, PI14/00618, PI14/00696, PI14/01206, PI14/01919, PI14/00853, PI14/01374, PI14/00972, PI14/00728, PI14/01471, PI16/00473, PI16/00662, PI16/01873, PI16/01094, PI16/00501, PI16/00533, PI16/00381, PI16/00366, PI16/01522, PI16/01120, PI17/00764, PI17/01183, PI17/00855, PI17/01347, PI17/00525, PI17/01827, PI17/00532, PI17/00215, PI17/01441, PI17/00508, PI17/01732, PI17/00926, PI19/00957, PI19/00386, PI19/00309, PI19/01032, PI19/00576, PI19/00017, PI19/01226, PI19/00781, PI19/01560, PI19/01332, PI20/01802, PI20/00138, PI20/01532, PI20/00456, PI20/00339, PI20/00557, PI20/00886, and PI20/01158); the Especial Action Project entitled Implementación y evaluación de una intervención intensiva sobre la actividad física Cohorte PREDIMED-Plus grant, the Recercaixa grant (2013ACUP00194), Grants from the Consejería de Salud de la Junta de Andalucía, a grant from the Generalitat Valenciana, a SEMERGEN grant, and funds from the European Regional Development Fund (CB06/03; CB12/03), The International Nut & Dried Fruit; and the AstraZeneca Young Investigators Award in Category of Obesity and T2D 2017 to DR. J.S.-S. is partially supported by ICREA under the ICREA Academia programme. None of the funding sources took part in the design, collection, analysis, or interpretation of the data or in the decision to submit the manuscript for publication