About this trial

The overall objective of this study is to evaluate the effectiveness of an optimized lifestyle intervention based on dietary advice, behavioral support, and provision of key foods compared to dietary advice with behavioral support or dietary advice alone. The intervention aims to improve nutritional status, metabolic risk factors, and planetary sustainability.

A total of 300 participants (150 men and 150 women) who meet all inclusion criteria and none of the exclusion criteria will be recruited. The study will be conducted at the Centre for Lifestyle Intervention at Östra Hospital in Gothenburg, led by researchers from Chalmers University of Technology, University of Gothenburg, and Sahlgrenska University Hospital. Participants will be recruited from two different socioeconomic areas in Gothenburg to examine how dietary interventions function in diverse population groups.

The study follows a twelve-week randomized, controlled, parallel intervention design. Participants will be randomized into three groups, each with 100 individuals:

Optimized lifestyle intervention group - receiving dietary advice, behavioral support, and provision of key foods.

Behavioral support intervention group - receiving dietary advice and behavioral support.

Control group - receiving dietary advice according to the SWITCH diet. The SWITCH diet, developed within the EU project SWITCH, is designed to align with European dietary guidelines and promote sustainable and healthy eating habits. It emphasizes whole grains, vegetables, fruits, legumes, and sustainable seafood while limiting processed foods, added sugars, and salt.

Throughout the study, participants will undergo clinical assessments at baseline, midpoint (week 7), and endpoint (week 13). Key measurements include anthropometric data, blood pressure, blood glucose, blood lipids, and inflammatory markers. Dietary intake and sustainability aspects of food consumption will also be evaluated. Participants in the intervention groups will receive personalized coaching and access to practical resources, such as meal plans, recipes, and visual educational materials.

The primary outcome of the study is the difference in cardiometabolic risk factors (e.g., blood lipids, blood pressure, glucose, insulin resistance markers) between the intervention groups. Secondary outcomes include changes in dietary intake, nutritional status markers, inflammatory markers, and sustainability measures (e.g., CO₂ emissions, land use, biodiversity impact). Additionally, exploratory analyses will investigate associations between diet, lifestyle changes, gut microbiota, and metabolic responses.

This study aims to generate valuable insights into the effectiveness of different dietary intervention strategies in real-life Nordic conditions. The results will contribute to the development of evidence-based recommendations for sustainable and health-promoting dietary patterns.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

Age 18-70 years

Body mass index 25-35 kg/m2

Stable dietary patterns at the entry to the study (no specific dieting the last 4 weeks).

Willingness to adhere to advised diet pattern and to consume provided key foods.

Disqualifiers

Currently having an infection or other relevant illness.

Cardiovascular events (myocardial infarction or stroke) during the previous 6 months. To be included, the disease needs to be stable.

Diagnosis of diabetes (any type).

Blood Pressure (BP): ≥185/105 mmHg.

Trial design

Design model

Parallel

Treatments tested in this trial

Behavioral Treatment
Behavioral
Behavioral support is designed to help participants adhere to the dietary recommendations through personalized coaching and motivational strategies. Participants engage in weekly or bi-weekly coaching sessions, either online or in person, where they receive guidance on overcoming challenges and maintaining dietary changes. The coaching incorporates evidence-based behavior change techniques, such as goal setting, self-monitoring, feedback on performance, problem-solving, and stimulus control. To further support behavior change, participants receive practical tools, including visual aids, educational videos, and structured meal planning resources. The overall goal of behavioral support is to encourage sustainable dietary habits by providing continuous encouragement and individualized strategies.
Food support
Behavioral
Food support, which is provided exclusively to participants in the Optimized Lifestyle Intervention Group, ensures that they have access to key foods required to meet dietary targets. These foods include whole grains such as whole grain bread, oats, and pasta; vegetables in both fresh and frozen forms; fruits and berries, including apples, pears, and frozen berries; legumes such as lentils, beans, and chickpeas; and seafood, including fatty fish, lean fish, and mussels. To facilitate adherence, participants also receive recipes and meal plans that incorporate these foods. Some fresh food items are made available at supermarkets near participants' residences to improve accessibility and convenience. Food support aims to reduce barriers to dietary change by ensuring that participants have the necessary ingredients to follow the SWITCH diet effectively.
Dietary Advice
Behavioral
Dietary advice consists of a simple document outlining the SWITCH diet, which is based on European and Nordic dietary guidelines. Participants receive this information in written form without any additional guidance, counseling, or support. The SWITCH diet emphasizes increased consumption of whole grains, vegetables, fruits, legumes, and seafood while limiting processed foods, added sugars, and excessive salt.

Treatment groups

300 Participants

are divided into 3 treatment groups

Group A: Optimized lifestyle intervention groupExperimental treatment 3 interventions

Group B: Behavioral support intervention groupActive comparator 2 interventions

Group C: Control groupOther 1 intervention

Trial outcomes

Primary outcomes

1

LDL cholesterol

Changes in fasting LDL cholesterol

Time frame