Information and communication technology (ICT)-based digital health is an important tool for addressing diverse medical challenges. Numerous attempts have been made to integrate digital health into medical fields. For example, in diabetes management, leveraging digital health has shown promise in pre-clinical and remote clinical trials.¹ A digital approach can enhance patient education, advance blood glucose monitoring and adherence, and facilitate the assessment and management of complications, engaging healthcare professionals directly.¹ Prior studies have underscored the potential advantages of digital health, exemplified by the positive impact and considerable satisfaction derived from using Diabetes Notepad, a mobile application designed for enhancing diabetes self-care.²

Moreover, amid heightened health awareness due to the coronavirus disease-2019 (COVID-19) pandemic, there has been a surge in efforts to incorporate ICT-based technologies into healthcare functions.³ South Korea’s remarkable surge in medical application downloads during the pandemic highlights its steadfast commitment to integrating digital health into everyday medical practices.⁴

According to the Obesity Statistics by the Numbers (2023) publication of the Korean Society for the Study of Obesity (KSSO), the prevalence of obesity in Korea has risen persistently over the past decade, particularly the number of individuals classified as obese class 2 and 3. In 2021, 49.8% of men and 27.8% of women were classified as obese with a body mass index (BMI) of 25 kg/m² or more.⁵ The World Health Organization (WHO) considers obesity an epidemic that poses a significant threat to public health.⁶ However, due to the rampant prevalence of the disease, misleading information about obesity has proliferated on the internet. To counteract this, the KSSO is currently disseminating authoritative information on obesity through the Clinical Practice Guidelines for Obesity.⁷

Traditional weight loss methods have focused on reducing calorie intake below expenditure, employing calorie restriction, and increasing physical activity.⁸ This trend has propelled the evolution of mobile health (mHealth) applications centered on monitoring food intake and exercise. Smartphone applications for weight loss are simple-to-use, convenient tools that allow individuals to manage their health in addition to enabling continuous monitoring of calorie intake, physical activity, and weight at any time of the day, facilitating a more detailed and sustained management approach compared to conventional methods.⁹ Aligning with this trend, the KSSO launched the Weight Management Obesity Note application in November 2022, marking the initial phase of nationwide obesity management.

Obesity predominantly stems from an individual’s lifestyle behaviors, encompassing diet, activity levels, and stress management. Therefore, cognitive-behavioral therapy directed at behavior modification stands as the cornerstone of obesity treatment. Comprehensive lifestyle interventions target three main areas: controlling food intake, increasing physical activity, and employing behavioral therapy techniques. These strategies have long proven efficacious in enhancing compliance with prescribed meal and activity regimens, culminating in superior outcomes for obesity treatment.¹⁰ Standard lifestyle interventions include maintaining a daily diary of food intake and physical activity, conducting weekly weight checks, following structured curricula akin to those in diabetes prevention programs, and receiving regular feedback from physicians. These elements are integral parts of the KSSO mHealth application.¹⁰

The objective of obesity treatment transcends mere weight loss; treatment aims to curtail the diseases stemming from obesity and foster better overall health. Earlier studies, outlined in Table 1, have targeted a 5% to 10% reduction in baseline weight, a range recognized to offer substantial clinical benefits.¹⁰ For instance, shedding 5% to 10% of total body weight within 6 months significantly reduces morbidity, disability, and mortality linked to obesity-related diseases, and notably enhances quality of life. In individuals with smaller weight losses of 3% to 5%, improvements in risk factors associated with cardiovascular diseases such as high blood pressure, type 2 diabetes mellitus, and dyslipidemia have been reported.¹¹ These parameters, pivotal for healthcare, underscore the importance of tracking user data.

Created by the IT-Convergence Metabolic Syndrome Treatment Committee of the KSSO, Weight Management Health Note aims to assist individuals in weight management and overall health enhancement. The application offers life-tracking tools such as a food diary, exercise tracker, and weight monitor, coupled with tailor-made lifestyle recommendations based on individual preferences and goals. Users have the autonomy to personalize commitments and share them while being rewarded with badges and receiving weekly progress reports for motivation and guidance. Access to an abundance of evidence-based health content ensures users access accurate obesity management insights. The overall flowchart of the application is depicted in Fig. 1.

Getting started

Upon initial application launch, users provide sign-up information and complete a detailed questionnaire. Based on their responses, the application formulates specific lifestyle improvement objectives aligned with user data. This 14-question survey meticulously evaluates water intake, dietary habits, drinking patterns, and daily physical activity, juxtaposing them with pre-entered information to create a personalized management plan.

The five core functions of the application: weight, eating, exercise, sleep, and drinking

Weight Management Health Note revolves around weight management, concentrating on regulating dietary intake, exercise, sleep patterns, and alcohol consumption. Fig. 2 showcases the application’s primary screens and functionalities, thoroughly evaluated in Table 2 within the KSSO’s clinical practice guidelines. For instance, under question-and-answer 5–2, the application advises users to “evaluate alcohol consumption during behavioral therapy for weight loss and maintenance.” Moreover, as presented in chapters 8, 9, 10, and 13, users in different circumstances are suggested to focus on different types of interventions. Binge eating and weight maintenance are also considered in the application. Weight Management Health Note considerations correspond well with those outlined in clinical practice guidelines. Once users input their data, the application generates an intuitive graphical representation depicting changes over time. The application evaluates and records several aspects pivotal to health management. First, it examines weight metrics, encompassing the latest measurements and deviations from the target weight, allow tracking of progress and goal attainment. Second, it employs BMI to assess obesity. Third, it meticulously tracks food intake, detailing total calorie consumption and the balance of nutrients—carbohydrates, proteins, and fats—over the preceding 2 months. Fourth, it captures exercise data, encompassing overall calorie expenditure, diverse exercise types undertaken, and their respective durations. Furthermore, it scrutinizes sleep patterns, recording the average daily duration of sleep and instances of disruptions. Lastly, it monitors drinking habits, analyzing the frequency and quantity of weekly alcohol intake.

These functionalities align with the five core features identified through lifestyle missions that were established based on an initial survey. Users can engage with distinct categories displayed in Fig. 3. The application offers the flexibility to log various meal types—breakfast, lunch, dinner, or snacks—by specifying date, time, food choices from a list with adjustable portions, and automated nutritional data capture, including the option to add a photo. Exercise inputs allow users to input exercise type, duration, and steps tracked automatically by the user’s phone. Caloric expenditure from exercises is automatically calculated based on predefined values. The recent application version 1.0.3 leverages the smartphone’s pedometer for automatic activity tracking. Sleep data entry includes bedtime, wake-up times, and the selection of sleep disorder symptoms (insomnia, narcolepsy, snoring, restless legs, sleep apnea, or others). Users can also log their drinking habits, specifying the type, duration, units, and quantity of alcohol consumed in glasses. The system then intuitively evaluates these inputs, offering ratings like ‘good,’ ‘recommended,’ or ‘poor’ to reflect activity levels.

In the remaining meal-related categories, whether the user had breakfast and whether a heavy meal was consumed are automatically logged alongside meal entry. However, other meal-related aspects like eating speed, fasting, broth intake, instant meal frequency, vegetable intake, and fruit intake require manual input from the user. Additionally, users can manually select the frequency of weight measurements: once a day, at least once a week, or once or twice a month.

On the mission screen, users view the “remaining calories,” representing unconsumed calories for the day. This feature subtracts the user’s eaten calories and recalculates burnt calories through exercise from the recommended intake based on the user’s body information.

Reports and rewards

Weekly reports detail user-entered answers, cumulative physical activity, and drinking habits. The reward system grants badges upon completing sleep challenges (7 to 8 hours per day), exercise challenges (100 to 300 minutes per week), refraining from daily alcohol consumption, and achieving specific nutrition goals, such as avoiding overeating or excessive fasting.

Resolutions and health information

Users can create resolutions, select the commitment’s background color, and compose a 40-character commitment within the application. The resulting commitment can be saved as an image and shared on social media. Health information encompasses nine categories, covering obesity facts, treatment, various exercises, and a question-and-answer section through categorized subtopics and video-supported tips. Note that the health information category is current inactive (January 2024).

Google Play Store alone hosted 54,546 mHealth applications by the third quarter of 2022.¹² Weight Management Health Note stands out due to the extensive expertise incorporated within the application by KSSO’s expertise encompassing knowledge across multiple medical disciplines. This application is a promising primary tool for chronic disease treatment and essential ICT-based medical aid tool that can benefit the wider public. While previous studies have underscored the efficiency of ICT interventions for obesity (Table 1)^10-15, further clinical trials are crucial to substantiate its effectiveness, ensuring its viability beyond theoretical foundations. The fusion of professionalism and ICT elements within Weight Management Health Note could potentially make this application the most effective application currently available for self-management of obesity and related diseases.

The authors declare no conflict of interest.

The authors would like to thank Former Chairman Ki-jin Kim, President Chang-Beom Lee, and all executives of the Korean Society for the Study of Obesity. In addition, the corresponding author would like to express thanks to Professors Emeriti Young Seol Kim and Young Kil Choi from Kyung Hee University for their exceptional teaching and inspiration.

Study concept and design: SK, DAC, and SYR; acquisition of data: DAC and SYR; analysis and interpretation of data: YL and HS; drafting of the manuscript: YL, HS, and SK; critical revision of the manuscript: SYR; and study supervision: SYR.