A systematic review of baseline psychosocial characterisation in dietary randomised controlled trials for weight loss

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 < 13 points or any increase if baseline score was ≥ 13 points. We conducted crude and adjusted multivariable logistic regression models to identify baseline factors related to compliance.

Results

Consistent factors independently associated with successful dietary change at both 6 and 12 months were high baseline perceived self-efficacy in modifying diet (OR_6-month: 1.51, 95% CI 1.25–1.83; OR_12-month: 1.66, 95% CI 1.37–2.01), higher baseline fiber intake (OR_6-month: 1.62, 95% CI 1.07–2.46; OR_12-month: 1.62, 95% CI 1.07–2.45), having > 3 chronic conditions (OR_6-month: 0.65, 95% CI 0.53–0.79; OR_12-month: 0.76, 95% CI 0.62–0.93), and suffering depression (OR_6-month: 0.80, 95% CI 0.64–0.99; OR_12-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.

Trial registration

ISRCTN registry 89898870, 24th July 2014 retrospectively registered http://www.isrctn.com/ISRCTN89898870.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02697-8.

Baseline Depressive Symptoms, Completion of Study Assessments, and Behavior Change in a Long-Term Dietary Intervention Among Breast Cancer Survivors

Background

Depressive symptoms can lower adherence and change in dietary studies. Behavioral activation may reduce these effects.

Purpose

This study aims to assess relationships among depressive symptoms on adherence and dietary change in the Women’s Healthy Eating and Living (WHEL) Study

Methods

Secondary analyses from the WHEL Study, which achieved major dietary change in breast cancer survivors (N = 2817), were conducted. Logistic regressions were undertaken of baseline depressive symptoms (six-item Center for Epidemiologic Studies Depression Scale (CES-D)) with (1) completion of 1- and 4-year study assessments and (2) validated change in dietary behavior in the intervention group.

Results

In the comparison group (vs. intervention), depressive symptoms lowered completion of dietary recalls and clinic visits [4 years: odds ratio (OR) = 2.0; 95 % confidence interval (CI) = 1.4–3.0]. The behaviorally oriented intervention achieved major change in those furthest from study targets, although changes were lower in those with depressive symptoms: fruit/vegetable (+37.2 %), fiber (+49.0 %), and fat (−22.4 %).

Conclusions

Behavioral activation in dietary change interventions can overcome the impact of depressive symptoms.