Who benefits from a dietary online intervention? Evidence from Italy, Spain and Greece

Abstract

Objective: The traditional Mediterranean diet includes high consumption of fruits, vegetables, olive oil, legumes, cereals and nuts, moderate to high intake of fish and dairy products, and low consumption of meat products. Intervention effects to improve adoption of this diet may vary in terms of individuals' motivational or volitional prerequisites. In the context of a three-country research collaboration, intervention effects on these psychological constructs for increasing adoption of the Mediterranean diet were examined. Design: An intervention was conducted to improve Mediterranean diet consumption with a two-month follow-up. Linear multiple-level models examined which psychological constructs (outcome expectancies, planning, action control and stage of change) were associated with changes in diet scores. Setting: Web-based intervention in Italy, Spain and Greece. Subjects: Adults (n 454; mean age 42·2 (SD 10·4) years, range 18-65 years; n 112 at follow-up). Results: Analyses yielded an overall increase in the Mediterranean diet scores. Moreover, there were interactions between time and all four psychological constructs on these changes. Participants with lower levels of baseline outcome expectancies, planning, action control and stage of change were found to show steeper slopes, thus greater behavioural adoption, than those who started out with higher levels. Conclusions: The intervention produced overall improvements in Mediterranean diet consumption, with outcome expectancies, planning, action control and stage of change operating as moderators, indicating that those with lower motivational or volitional prerequisites gained more from the online intervention. Individual differences in participants' readiness for change need to be taken into account to gauge who would benefit most from the given treatment. Keywords Dietary change Digital interventionAction planning Action control Outcome expectancies Stages of change Online surveyThe traditional Mediterranean diet includes high consumption of fruits, vegetables, olive oil, legumes, cereals and nuts, moderate to high intake of fish, moderate intake of dairy products and low consumption of meat products. It has been found to protect overall health and is associated with a low risk of CVD (1)(2)(3)(4) and certain cancers (2,3,(5)(6)(7) . Accordingly many institutions have recommended adopting and maintaining nutritional habits in line with this type of diet, and in particular with a focus on fruit and vegetable consumption.Although the WHO has advised to eat at least five portions of fruit and vegetables daily, globally fruit and vegetable consumption is lower than this recommendation (8,9) . Thus, behavioural interventions are needed to promote the Mediterranean diet. Social-cognitive mechanisms of behaviour change can serve as a psychological underpinning of such interventions and a number of relevant intervention components have been identified (10) . Most of this research examines main effects of predictors such as attitudes, motivation, planning...

The Promotion of Eating Behaviour Change through Digital Interventions

“…Elapsed time also significantly affected goal attainment ( p < 0.001). Schwarzer et al [ 53 ] investigated the effects of a lifestyle intervention delivered by an online platform, which addressed four psychological constructs to change dietary behaviour in adults. Using a Mediterranean diet adherence screener, participants who had lower expectancies of positive outcomes gained more from the intervention.…”

“…Three studies [ 52 , 55 , 58 ] were rated high risk in the “deviations from intended interventions” domain due to lack of appropriate analysis (e.g., sensitivity analysis) to estimate the effect of assignment to intervention which has a potential substantial impact on the results. Those rated as some concern in the same domain [ 51 , 53 , 54 , 56 , 57 , 60 , 62 ] also lack appropriate analysis, but without a potential substantial impact on the results. All studies rated as some concerns in the “randomization process” [ 56 , 57 , 58 ] were not fully randomized while the one rated high risk [ 52 ] were also not fully randomized, and the baseline differences between intervention grouped suggested a problem with the randomization process.…”

Social support, adherence to Mediterranean diet and physical activity in adults: results from a community-based cross-sectional study

“…This cross-sectional study used baseline data from the CREDITS4HEALTH (C4H) study, a parallel-group, multi-centre, randomised controlled community-based trial (RCT). The C4H study aimed to assess the effects of an online platform that supports people in enhancing their level of physical activity and adopting a healthy Mediterranean diet by means of a person-centred approach, providing personalised plans and suggestions along with psychological and social support ( 22 ) .…”

The Mediterranean Diet in the Stroke Belt: A Cross-Sectional Study on Adherence and Perceived Knowledge, Barriers, and Benefits

“…A survey was developed to assess MedDiet adherence, participants’ stage of change towards adopting the MedDiet, perceived benefits and barriers of the MedDiet, and demographic variables. MedDiet adherence was evaluated using a validated 14-question Mediterranean Diet Adherence Screener (MEDAS) [24] that has been used to assess MedDiet adherence in countries bordering the Mediterranean Sea basin and elsewhere in the world, including the southeast U.S. [25,26,27,28] (Supplementary Materials Table S1). Three questions were asked to assess participants’ readiness to adopt a MedDiet using the Precaution Adoption Process Model (stages of change) [16] (Supplementary Materials Table S2).…”