Intervention Based on the Dietary Guidelines for the Brazilian Population for the Treatment of Overweight and Obesity

Efficacy of an Intervention Based on the Dietary Guidelines for the Brazilian Population in the Treatment of Overweight and Obesity: A Randomized Clinical Trial

This clinical trial aims to evaluate how group-based food and nutrition education interventions, grounded in the recommendations of the Dietary Guidelines for the Brazilian Population, can improve participants' dietary quality and support the treatment of overweight and obesity.

The study seeks to determine whether individuals with overweight and obesity receiving outpatient care who participate in collective food and nutrition education activities achieve benefits similar to those receiving individual nutritional counseling, particularly improvements in dietary intake, clinical parameters, and anthropometric measures.

Participants will be divided into two groups and will be required to attend four monthly sessions, complete questionnaires before and after the sessions, and provide consent for the collection of data from their medical records.

Researchers will compare the outcomes of participants attending group sessions with those receiving individual care to assess whether collective actions provide similar benefits in improving dietary quality, blood test results, and anthropometric measures.

Study Overview

• Status: Active, not recruiting
• Conditions: Obesity & Overweight; Overweight (BMI > 25)
• Intervention / Treatment: Behavioral: Control Group: Individualized Care; Behavioral: Collective Intervention Based on the Dietary Guidelines for the Brazilian Population

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Brazil
  • Rio Grande do Sul
    • Porto Alegre, Rio Grande do Sul, Brazil, 90050170
      • Federal University of Health Sciences of Porto Alegre

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adults (≥18 years of age)
• Individuals of both biological sexes
• Body Mass Index (BMI) ≥ 25 kg/m²

Exclusion Criteria:

• Pregnant or lactating women
• Cognitive, neurological, or psychiatric disorders that interfere with study compliance or participation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Individual Care Control Group; The control group will receive individualized nutritional counseling comprising four in-person consultations over a 4-month period.	Behavioral: Control Group: Individualized Care; The control group will receive individualized nutritional counseling consisting of four in-person consultations, conducted once monthly over a four-month period. Each session, lasting 50-60 minutes, will be led by a nutritionist. These consultations will focus on establishing goals for dietary habit modification and on developing a personalized nutritional plan to improve overall dietary quality.
Experimental: Collective Intervention Group based on the Dietary Guidelines for the Brazilian Population; Participants will attend four monthly collective Food and Nutrition Education sessions.	Behavioral: Collective Intervention Based on the Dietary Guidelines for the Brazilian Population; Participants in the intervention group will attend four monthly in-person Food and Nutrition Education sessions based on the Dietary Guidelines for the Brazilian Population. These sessions will facilitate discussions on healthy eating and incorporate activities designed to dispel nutritional myths. The curriculum will address the NOVA classification system, critical appraisal of food labels, and making informed food choices. Additionally, a culinary workshop will feature healthy, affordable recipes. This component aims to enhance culinary skills, broaden dietary repertoire, and ultimately reduce the consumption of ultra-processed foods.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dietary Assessment	Dietary intake will be assessed using the 24-hour dietary recall available on the Quest Nova platform. This instrument consists of 58 items featuring common foods in the Brazilian diet; participants indicate the consumption of each item via dichotomous (yes/no) responses. The estimated completion time for the questionnaire is 15 minutes. This tool enables the identification of both quantitative and qualitative aspects of the participants' dietary habits. To ensure a representative average of intake, the assessment will be administered twice within the same week, both at baseline (pre-intervention) and post-intervention.	Before and After the 4-Month Interventions
Dietary Practice Scale of the Dietary Guidelines for the Brazilian Population	Adherence to healthy eating practices will be measured using the Dietary Practice Scale based on the Dietary Guidelines for the Brazilian Population. This validated, self-administered instrument consists of 24 statements regarding healthy dietary habits as recommended by the guidelines. For each statement, participants indicate their level of adherence using a 4-point Likert scale ranging from "Strongly Agree" to "Strongly Disagree." The scale is a robust tool designed to quantify compliance with national dietary recommendations and to evaluate the overall quality of food-related behaviors.	Before and After the 4-Month Interventions

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body Mass Index (BMI)	BMI will be calculated as weight (kg) divided by height squared (m²).	Before and after the 4-month interventions
Waist circumference	Waist circumference will be measured using a non-elastic measuring tape at standardized anatomical landmarks. Measurements will be taken three times, and the mean value will be used. Unit of Measure is centimeters (cm).	Before and after the 4-month interventions
Fasting blood glucose	The data will be collected from medical records. The unit of measurement used will be mg/dL.	Before and after the 4-month interventions
Glycated hemoglobin (HbA1c)	Medical records will be used to gather data. Unit of Measure will be %	Before and After the 4-Month Interventions
Total cholesterol	Data will be gathered from medical records. Unit of Measure will be mg/dL	Before and After the 4-Month Interventions
HDL cholesterol	Data will be collected from medical records. Unit of Measure will be mg/dL	Before and After the 4-Month Interventions
LDL cholesterol	Data will be collected from medical records. Unit of Measure will be mg/dL	Before and After the 4-Month Interventions
Triglycerides	Data will be collected from medical records. Unit of Measure will be mg/dL	Before and After the 4-Month Interventions
C-reactive protein	Data will be collected from medical records. Unit of Measure will be mg/L	Before and After the 4-Month Interventions
Uric acid	Data will be collected from medical records. Unit of Measure will be mg/L	Before and After the 4-Month Interventions
Transtheoretical Model of Change	Stage of behavior change will be assessed using the Transtheoretical Model (Prochaska Scale), in which participants will be classified into one of five stages (pre-contemplation, contemplation, preparation, action, or maintenance) based on their readiness to engage in weight management behaviors, and the outcome will be analyzed as a categorical variable representing the participant's stage of change (5 levels).	Before and after the 4-month interventions

Collaborators and Investigators

• Sponsor: Federal University of Health Science of Porto Alegre
• Collaborators: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

Publications and helpful links

Helpful Links

• Dietary Guidelines for the Brazilian Population
• Obesity: preventing and managing the global epidemic. Report of a WHO consultation.
• CONSORT 2025 statement: updated guideline for reporting randomised trials
• Ultra-processed foods and health outcomes: systematic review

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2025
• Primary Completion (Estimated): November 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: March 31, 2026
• First Submitted That Met QC Criteria: April 15, 2026
• First Posted (Actual): April 20, 2026

Study Record Updates

• Last Update Posted (Actual): April 20, 2026
• Last Update Submitted That Met QC Criteria: April 15, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Obesity; Overweight; Nutrition Education
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Overweight; Obesity
• Other Study ID Numbers: ECRGAPB26

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Due to the sensitive nature of the clinical data and the absence of a data-sharing clause in the Informed Consent Form, these records will not be made publicly available. Access will be strictly limited to the primary investigators.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No