Evaluation of the Computer-Based Intervention Program Stayingfit Brazil to Promote Healthy Eating Habits: The Results from a School Cluster-Randomized Controlled Trial

Brito Beck da Silva, Karine, Naiá Ortelan, Sheila Giardini Murta, Isabel Sartori, Ricardo David Couto, Rosemeire Leovigildo Fiaccone, Maurício Lima Barreto, Megan Jones Bell, Craig Barr Taylor, and Rita de Cassia Ribeiro-Silva

International Journal of Environmental Research and Public Health 16, no. 10 (2019): 1674


To promote healthy eating habits and lifestyles among adolescents, researchers have explored computer-based nutritional interventions as a potentially cost-effective means of reaching a large population. Despite the pressing need for such health tools and the recent surge in internet access in Brazil, these interventions have only recently been introduced in the country. To assess the efficacy of computer-based interventions in promoting healthy eating habits and weight management among Brazilian youth, this study evaluated the online program StayingFit Brazil among 7th to 9th grade students in Salvador, Bahia, Brazil, over the course of one year.


StayingFit is an online program developed by Stanford University and adapted to the local setting. The program had 16 sequential, independent sessions about nutrition and healthy eating practices, physical activity, and healthy lifestyles. Students accessed the program in school once a week for 30 minutes.   After completing each session, students were quizzed about what they learned and asked to provide feedback on the content. They completed food intake and physical activity logs and received recommendations based on guidelines from the World Health Organization and the Food Guide for the Brazilian Population 2014. Students were also encouraged to record their goals for the program and to participate in discussion forums. Information about the sessions was also shared with parents and teachers. 


Design: The evaluation took place in 12 public schools from September 2016 to September 2017. Researchers randomly assigned each school to receive either the StayingFit intervention or no intervention and thus serve as a comparison group (cluster randomized controlled design). Four schools were assigned to the intervention and eight schools to the comparison group. Researchers collected anthropometric measurements (body mass index (BMI), hip circumference, arm circumference, and waist-to-height (WH) ratio) at the beginning and end of the study. Students self-reported their food consumption, physical activity, and sedentary behavior at baseline and after 12 months. 

Sample: A total of 1,800 male and female 7th, 8th, and 9th graders were eligible to participate in the study; 895 (50%) provided informed consent and were included in the analysis. Around 30% of the students dropped out in the middle of the study.

Students in the study had an average age of 14.5, and half (52%) were male. About a third (27%) came from households with low education attainment. At the beginning of the study, more than half (64%) were categorized as sedentary. A majority (71%) of students were within the normal range for BMI-for-age and one in five (23%) students were considered overweight.  


Across all participants, there were improvements in some anthropometric measures, including BMI, WH ratio, and hip circumference, and healthy food intake at the endline. But when compared to each other, the intervention and comparison groups did not differ in anthropometric improvements. Students in the intervention group, however, were more likely than the control group to eat more beans—an important source of nutrients and fiber—and to drink fewer soft drinks than they did at the beginning of the study. 

Limitations: This study was limited by the high attrition rate, due to students dropping out of school or not completing the study. Additionally, self-reported measures of diet and exercise were used to assess changes in behaviors.


The modest improvements observed in students’ healthy food intake with StayingFit Brazil could potentially reduce their risk for obesity and thus their risk for noncommunicable diseases early in life. Whether these positive behavior changes can be maintained for a longer period warrants further research. Future studies should continue to build the evidence base for the potential of computer-based interventions to affect nutritional behavior among adolescents and help them maintain healthy habits throughout their lives.