The Smartphone-assisted Intervention Improved Perception of Nutritional Status Among Middle School Students

Shen, Yan-Hui, Zheng Liu, Wen-Hao Li, Shuang Zhou, Jin-Hui Xu, Chu Jiang, and Hai-Jun Wang

International Journal of Environmental Research and Public Health 17, no. 16 (2020): 5932


Children may not be motivated to practice healthy lifestyles due to inaccurate perceptions of their nutritional status, resulting in poor nutrition and weight management that could develop into obesity. In this study, researchers examined the effectiveness of a smartphone-assisted intervention on improving nutritional status perception among Chinese middle-school children and their parents in Beijing in 2019. 


In the first month of the study, students and their parents received three 30- to 40-minute sessions about obesity consequences, weight management, and weight perception. In addition, students’ body mass indexes (BMIs) were calculated at baseline and one month later; students demonstrating excess weight gain at the one-month follow-up and their parents received feedback by phone, and students were encouraged to weigh themselves weekly. Lastly, parents were asked to install the “Measure Your Nutritional Status” application on their phones and input student age, sex, weight, and height data from baseline and one-month follow-up assessments with research staff, and weekly thereafter for three months. The application shared regular updates on students’ nutritional status.  


Design: Conducted in Haidian District, Beijing, from March to June 2019, the study included intervention and control groups, but students were not randomly assigned to either group (non-randomized parallel-group control trial). Students in the control group did not receive any part of the intervention. 

Researchers focused on two primary outcomes: the percent of students with an accurate perception of their nutritional status and the percent of parents with an accurate perception of their child’s nutritional status. Research staff measured student weight and height and students and parents completed a questionnaire on weight perception and related behaviors. Their perceptions were compared to the students’ actual nutritional status (determined using age- and sex-specific BMI calculations) and then categorized as either accurate  or inaccurate. Secondary outcomes included the percentages of overestimates and underestimates, as well as the students’ BMIs, BMI Z-scores, and the percent of students who were contemplating or beginning to change their behavior to manage their weight. 

Sample: Students from three middle schools were invited to participate. Eligible schools should not have implemented an obesity prevention program in the prior year, which could have altered perceptions in the study. Of 638 students recruited, 573 (90%) were enrolled in the study. Of those, 543 (95%) completed both the baseline and the three-month follow-up assessments, resulting in 245 students receiving the intervention and 298 serving as controls. The sample had an average age of 13.1 years, and a majority (60%) had mothers who attained education above high school level. At baseline, 64% were considered normal weight and 35% were overweight or obese. 


By the end of the study, students in the intervention group were more likely to have an accurate perception of their nutritional status. At endline, the percent of students with accurate perceptions in the intervention group increased by 10%, compared to a 6% decrease in the control group. These findings were supported by regression results, showing that students in the intervention group were about 70% more likely to improve their perception than control students. 

Among students whose parents initially had inaccurate perceptions of their nutritional status, the intervention had a stronger effect on students accurately perceiving their status by the end of the study compared to students whose parents had accurate perceptions. In addition, students in the intervention group were more likely than their control counterparts to consider changing their behavior related to weight management. The researchers did not observe any significant changes in parents’ perceptions or students’ BMIs. 

Limitations: The study’s non-randomized allocation of students to study arms is a limitation, as this may have resulted in a non-similar distribution of group characteristics that may have influenced the results. Additionally, the number of participating schools was very small.


The authors were able to show that a simple, smartphone-assisted intervention yielded promising results for obesity prevention in a group of Chinese middle-school children. While the intervention was not able to demonstrate changes in BMI, the improved weight perception observed in the study warrants further investigation using larger and longer-term studies to better examine the intervention’s effects.