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There is increasing recognition that personalized approaches may be more effective in helping people establish healthier eating patterns and exercise more, and that this approach may be particularly effective in adolescents.
The objective of this study was to investigate the use of a smartphone app (FoodWiz2) in supporting healthy lifestyle choices in adolescence.
Participants (N=34: 11 male, 23 female) aged 16-19 years in full- or part-time education were recruited from sixth form colleges, schools, and other further education establishments in Norfolk and Suffolk, United Kingdom, between February and May 2015. Participants recorded food intake and exercise using a paper diary for 4-5 weeks and then used the app for the same duration. Initial nutrition education and general support were provided during the paper diary use, but the app included personalized messages sent in response to app activity. At the end of each study phase, participants completed an online questionnaire to describe their experience of using the paper diary and app.
Record completion declined throughout the study, possibly affected by examination pressure. Food intake data showed increased fruit consumption and significantly reduced consumption of chocolate snacks (
This app-based approach has shown the potential for a more effective approach to improving adolescent diet and exercise levels.
A wide range of modern technologies designed to support health and well-being of individuals and specific populations are becoming available and increasingly affordable. This study was designed to investigate the use of a smartphone app (
Despite the implementation of public health campaigns, adherence to dietary advice is poor across many European countries [
Dietary intake can be measured by a range of approaches, such as 24-hour recall, food frequency questionnaires (either self-administered or by interview asking about relatively long-term eating habits based on food groups), food diaries, or duplicate diet measurement. The first 3 approaches rely on using food composition databases, which are continuously being improved for content and accuracy. Of the 3 approaches, arguably the most accurate for measuring current food intake is the food diary method, preferably recording weighed food intake for as many days as possible. The main drawback with this approach is that it is labor-intensive and most people will either modify their diet to save writing down small snacks, record inaccurately, or just give up on recording [
There is an increasing recognition that a personalized approach to nutritional modification may be more effective in helping people establish healthy eating patterns and, combined with encouragement to exercise more, lead to the establishment of better lifestyle habits [
Despite the proliferation of health-related apps and their apparent potential in dietary interventions, there is currently limited evidence on the experience of using these self-monitoring tools, and how participants perceive the comparison between novel and traditional methods of dietary assessment. Previous research into smartphone apps, personal digital assistants (PDAs), or short messaging service (SMS) interventions have attempted to assess participant experience, usually through questionnaires, and report on domains such as user satisfaction, patterns of usage, engagement, reasons for like or dislike, helpfulness, and influence on self-efficacy [
The aim of this study was to assess the ease of use, acceptability, and perceived effectiveness of a smartphone app for the measurement of food intake and exercise in adolescents compared with more traditional paper-based approaches.
All participants were initially asked to record food intake and exercise using a paper-based diary and then to use a smartphone app to record food and exercise as frequently and as accurately as they found feasible for 4-5 weeks. A 2-phase study design was chosen over a parallel intervention study to avoid introducing potential confounding effects, such as social factors, familiarity with the technology, and individual academic achievement. The study design also avoided potential carry-over effects and disproportionate dropout from the app-to-paper group that may have been associated with a conventional randomized crossover design. Personal and professional contacts were used to involve schools and colleges in the design of the study and to ensure that the protocol was appropriate in an educational environment with minimal disruption to pupils. The study was not blinded or randomized, but each participant was allocated a code for data analysis purposes. The study was scientifically reviewed by the Human Research Governance Committee at the Institute of Food Research, Norwich. The study was conducted according to the guidelines laid down in the Declaration of Helsinki, and all procedures involving human subjects were approved by the Oxford C Ethics Committee managed by the UK Health Research Authority (144/SC/1268).
Participants aged between 16 and 19 years, still in full- or part-time education, were recruited from sixth form colleges, schools, and other further education establishments in Norfolk and Suffolk, UK, between February and May 2015. The study was advertised through email and phone calls to education centers, followed by an initial presentation explaining the study first to the head and other interested staff and then to the students. The eligibility criteria were absence of chronic illness or disease (such as serious asthma or diabetes), not pregnant, able to give informed consent, have parental support, able or willing to use a smartphone, able to complete paperwork even with assistance, no eating disorders, no involvement in other research projects or weight management program, and not being related to any member of the study team. An inclusion criterion of BMI not below the second centile line on the BMI chart [
Eighteen schools in Norfolk and Suffolk were contacted via email, phone calls, or visit by the researcher. Five schools gave consent for the study talk to be delivered to their students. Recruitment for the study took place between February and May 2015. The flow of participants through the study is described in
Following consent, participants were screened based on the eligibility criteria. Weight was measured to the nearest 0.1 kg using a portable electronic scale (Salter Ultimate Accuracy, Tonbridge, Kent, UK); height was measured to the nearest millimeter using a portable stadiometer, and waist circumference was measured to the nearest millimeter using a body waist fitness caliper. Participants then completed a background information form, which provided more information about their diet, previous recording of diet or exercise, use of apps for similar purposes, and educational attainment. A score was calculated for the General Certificate of Secondary Education (GCSE) educational attainment based on a scale of 1-8 for grades G-A (including the higher level A* grade), and a cutoff of 25 (representing grade C in 5 subjects) was used to assess whether there was any difference in the interest in, or ability to, monitor diet among low and high academic achievers. The cutoff of 25 is used in the United Kingdom for assessing suitability at 16 years of age to progress to higher academic studies. Following screening, all participants received nutrition education sessions, covering the basics of a healthy diet, the importance of exercise, and different ways of achieving and maintaining a healthy nutrient intake and net energy intake based on government guidance.
Participants were initially provided with paper record sheets to record the day, date, time, type, and amount of all foods and drinks consumed; they could also record any recipe in the food record sheets. These food diaries were adapted from those previously used at The Institute of Food Research [
Diagram showing the flow of participants through the study.
After a short interval in recording (1-2 weeks), coincident with a school or college holiday, a smartphone app developed by Food Angels UK Ltd, Newmarket, Suffolk, UK, was given to participants to use for the following 4 weeks (screenshots are available in
At the end of each phase of the study, participants were asked to complete an online questionnaire (
For the analysis of reported food intake using paper diaries or the app, descriptive measures were calculated to describe the sample by use of percentages, means, and standard deviations. Fruits and vegetable servings per day were calculated by dividing the total fruit and vegetable servings consumed by the total number of days that eating occasions were recorded using either the paper diary or App as described by Aflague et al [
Two analyses were conducted on questionnaire data because of missing responses: answers to individual questions were described as percentages of all data provided with a subsequent comparison of responses for just those who included their unique identity code, allowing paired analysis of the responses given. The significance of differences in the values of responses to the questionnaire after each phase of the study was evaluated using the sign test for nonparametric paired ordinal data. This test is more conservative than the more frequently used Wilcoxon signed rank test but more appropriate for this dataset where it is difficult to prove the difference between pairs is ordinally scaled [
Microsoft Excel 2010 for Windows was used to enter the data, and statistical analyses were performed using SPSS, Version 22 (SPSS Inc., Chicago, IL, USA). All tests were 2-tailed and
Participants (23 female, 11 male) aged 16 to 19 years were recruited in this study (
The paper-diary phase was completed by 32 out of the 34 participants who started the intervention, whereas the subsequent App phase was completed by 30 out of the remaining 32 participants. Only 12% (4/34) of participants recorded on all the possible days (28 days in both phases). The mean number of study days completed (>500 kcal) for each 28-day phase is shown in
The mean percentage completion for the paper diary was 86 (SD 10), whereas that for the app was 61 (SD 7), although it should be noted that most students were taking examinations during the App-based phase. Completion rate decreased gradually throughout the study period both during the paper diary phase and the app phase (
Reported food intakes were analyzed by food groups, only for those days where >500 kcal were recorded to allow for comparison between results from the paper diary and the app. In general, recorded food intake was similar using either method; however, the reported consumption of chocolate snacks (
All participants recorded a range of exercises in the paper diaries, most frequently walking and cycling but also team sports, gym, dance, and housework. Similarly, all those still in the study used the app for this purpose on at least 1 occasion with 2 participants providing data for at least 26 days, in comparison with 8 participants using the paper diary. Interestingly, there was a significant correlation between the numbers of days completed in the paper diary and the app (
Characteristics of participants. SD: standard deviation; BMI: body mass index; GCSE: General Certificate of Secondary Education.
Characteristics | Male (n=11) | Female (n=23) | |
Age (years), mean (SD) | 16.8 (0.8) | 17.1 (0.85) | |
Weight (kg), mean (SD) | 75.6 (12.76) | 66.6 (12.59) | |
Height (m), mean (SD) | 1.8 (0.08) | 1.7 (0.06) | |
Waist circumference (cm), mean (SD) | 85.0 (12.88) | 79.1 (10.66) | |
BMI (kg/m2), mean (SD) | 24.6 (4.21) | 24.2 (4.64) | |
Normal (below the 91st centile) | 7 | 17 | |
Overweight (above 91st centile) | 1 | 4 | |
Very overweight or clinically obese (above 98th centile) | 2 | 0 | |
Severely obese (above 99.6th centile) | 1 | 2 | |
Vegetarian or vegan, n | 0 | 2b | |
Special diet, n | 0 | 1c | |
Allergies, n | 0 | 1d | |
Supplements, n | 3e | 0 | |
Previously recorded diet or exercise, n | 1 | 10 | |
Previous use of diet or exercise app, n | 2 | 4 | |
Below 25 GCSE points | 5 | 9 | |
25 and above GCSE points | 6 | 14 |
aBMI thresholds vary by sex and one-year increments in age. The age range covered is 2-20 years (Boys UK and Girls UK, Body mass index, 2-20 years [
bA participant became vegetarian after 2 weeks in the study (decision independent of the study).
cMild intolerance to wheat and dairy.
dPenicillin allergy.
eMultivitamins and glucosamine phosphate (n=1); protein occasionally and vitamin tablets in winter (n=1); vitamin D, Branch chain amino acids, whey protein and creatine monohydrate (n=1).
fA score was calculated for GCSE based on a scale of 1-8 for grades G-A (including the higher level A* grade). The cutoff of 25 is equal to grade C in 5 subjects.
Percentage completion of the study diary and App presented by weeks of the study. A completed day was regarded as a day with ≥500 kcal energy recorded [
Week | Percentage completion (SD) | Diet recording tool |
1 | 96 (4) | Paper diet record |
2 | 92 (7) | Paper diet record |
3 | 82 (2) | Paper diet record |
4 | 73 (7) | Paper diet record |
5 | 66 (8) | App |
6 | 61 (4) | App |
7 | 54 (3) | App |
8 | 64 (4) | App |
Analysis of records per food group for the paper diary and app. Data are expressed as an average per day on which a total >500 kcal was recorded. Errors are expressed as standard error of the mean (SEM, n= 32). There is a significant difference between the use of paper diaries and the app in the recording of chocolate snacks and fizzy drinks (a:
In most cases, no significant difference in response to Likert scale questions relating to the paper diary and the app were found. The free-text responses gave some additional insight into the issues raised (
The questions relating to patterns of use revealed that the reported level of use of the 2 approaches was similar, although the participants believed they used the paper diary for more days a week than the app (Question 1,
Using both the paper diary and the app were considered time-consuming for different reasons. The paper diary involved having to manually write information and weigh foods, whereas the app had technical issues, for example, it worked slower than anticipated (
Response to questionnaires in relation to how comfortable participants felt using the paper diary or app in different social scenarios. There is a significant difference between the use of paper diaries and the app in social settings (
Response to questionnaires in relation to participants’ general feelings towards using either the paper diary or app. For statements a, b, and c, there is a significant difference between the use of the paper diary and the app (a:
Most participants reported that the use of both the paper diary and the app raised awareness of what they had been eating and how active they had been, and they felt that the app was more effective in this respect, which was again consistent with actual recorded data for chocolate snacks and fizzy drinks. However, there were no significant differences in perceived effectiveness between the 2 methods. When indicating the overall preference between the paper diary and the app, 5 out of 12 participants preferred the app, 3 out of 12 preferred the paper diary, and 4 out of 12 had no preference. Participants reported performing more aerobic and strength exercises as well as trying new activities; however, this was not significant, and indeed, the App appeared to significantly reduce confidence to do more activities. This reduction may be explained by the comments about the lack of options in the set list for exercise on the app (
Adolescence is a key point in life in establishing long-term eating patterns as young people move forward into adult life with growing independence in food choice. Results of this study demonstrated that the app is a potentially feasible method of recording diet and physical activity in adolescents. Previous similar studies using smartphone apps with adults have focused on specific applications such as weight loss or caloric balance [
This study had several strengths including the fact that it focused on encouraging overall dietary improvement rather than calorie control in adolescents. This was considered a key issue, as some young people are very sensitive about their weight and may be particularly at risk of developing eating disorders such as anorexia or bulimia [
Free-text responses in the questionnaires indicated that using either the paper diary or the
Our results indicate that, in general, participants preferred the use of a smartphone app to the more traditional paper diary, although some technical issues need to be addressed. In particular, participants found it more comfortable to use the app in social settings. They perceived that the use of the app had more impact on their dietary intake as well as physical activity, compared with the paper diary. Analysis of data from the recorded food intake also showed significantly reduced consumption of chocolate snacks and fizzy drinks among participants when they used the app to record their food intake compared with using the paper diary. The use of mobile technology shows great promise for reducing the burden of self-monitoring lifestyle in this age group, but future apps need to be more sophisticated than the one used for this study. Finally, the relative ease of data extraction for the app compared with coding food diaries and the quality of detail provided mean similar tools show great promise for research purposes.
Screenshots from the FoodWiz2 app. A: the main menu; B: the home screen showing weight, daily targets, and mood; C: adding individual foods and portions.
The study questionnaire used following phase 1 (the paper diary).
The study questionnaire used following phase 2 (the App).
Free-text responses illustrating views expressed by participants responding to the questionnaire with free-text answers.
body mass index
General Certificate of Secondary Education
personal digital assistants
standard deviation
short messaging service
The authors would like to thank the participants who recorded their diet and activities using the paper diary and the FoodWiz2 app, and head teachers, heads of sixth forms, and staff in the schools and colleges where the study was completed. The authors also thank Pippa Belderson, Department of Social Work, School of Health Sciences, University of East Anglia, Norwich, UK, for advice on the design of the study questionnaire and the analysis of the free-text responses.
This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 613783 and from the Biotechnology and Biological Sciences Research Council Core Strategic Grant No. BB/J004510/1. The views expressed are those of the authors and not necessarily those of the European Union’s Seventh Framework Programme for research, technological development and demonstration.
JL is the owner of Food Angels UK Ltd, which developed the FoodWiz2 app. FJ and CF were employed by Food Angels UK Ltd to complete the study. EL was contracted by Food Angels UK Ltd to assist with the study design and implementation. All the other authors declare no conflict of interest.