The SWITCH Dietary and Behavioural Intervention Study

Summary

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.

Conditions

• Dietary Behaviour
• Dietary Intakes
• Dietary Intervention
• Metabolic Diseases
• Blood Lipid Profiles
• Blood Glucose Metabolism
• Diet, Healthy

Interventions

BEHAVIORAL

Behavioral Treatment

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.

BEHAVIORAL

Food support

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.

BEHAVIORAL

Dietary Advice

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.

Sponsors & Collaborators

• Göteborg University

  collaborator OTHER

• Vastra Gotaland Region

  collaborator OTHER_GOV

• Chalmers University of Technology

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

70 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-03-03

Primary Completion

2026-11-30

Completion

2026-11-30

Countries

• Sweden

Study Locations