Household configurations are experiencing rapid transformations attributed to the erosion of traditional family structures, a growing prevalence of individuals opting for single or nuclear family arrangements, and societal shifts, including advancements in women’s economic empowerment (1). According to recent findings from Statistics Korea, the incidence of single-person households in Korea has almost doubled, surging from 15.5% in 2000 to 29.9% in 2019, establishing it as the predominant family structure in the nation. Furthermore, projections indicate that single-person households are poised to constitute 37.7% of the total by 2047, with the sharpest growth rate observed among countries within the Organization for Economic Co-operation and Development. Particularly noteworthy is the pronounced rise among young adults aged 20–39, with a substantial increase in the number of women residing in single-person households (2). Single-person households have been linked to reduced physical activity and unhealthy dietary habits, heightening the risk of obesity in comparison to multi-person households (3, 4). Research on the general adult population in Korea indicates that individuals living alone tend to consume a higher proportion of energy from fats and a lower intake from carbohydrates and plant proteins (5, 6). This dietary pattern is associated with an increased risk of metabolic syndrome and obesity (6). Notably, single-person households in metropolitan areas in Korea exhibited a higher tendency to skip breakfast and experience food insecurity, factors that are linked to an increased risk of metabolic abnormalities such as obesity (7). Moreover, single-person households represent a vulnerable demographic at an elevated risk of social isolation, exacerbated by infectious diseases such as COVID-19 and subsequent social distancing measures. Such isolation often correlates with higher levels of stress and a lack of motivation, which can lead to coping strategies that include the increased consumption of sugary snacks and beverages (8, 9). These dietary choices, driven by emotional responses rather than nutritional needs, further compound the risk of metabolic abnormalities and obesity. Under these circumstances, the implementation of non-face-to-face intervention programs becomes imperative to address the multifaceted contributors to overweight within single-person households.

Epidemiological evidence, coupled with plausible mechanisms and clinical data derived from dietary intervention studies, strongly substantiates a direct causative link between sugar intake and metabolic diseases (10). Particularly, sugar-rich snacks and beverages represent prominent sources of added sugars in our dietary patterns. In a cross-sectional study encompassing 1,487 adults, there was a positive correlation observed between the consumption of sugary snacks and both body mass index (BMI) and waist circumference (WC) (11). Additionally, among overweight individuals aged 20–50 years, a 10-week intervention featuring a high sucrose intake (comprising 28% of total energy consumption), primarily through beverages, resulted in increased energy intake, body weight, and fat mass (12). The adverse impact of sugar-rich beverages on the development of obesity may be attributed to their ability to induce rapid and substantial elevations in blood glucose and insulin levels (12). Conversely, substituting sugar-sweetened beverages with either artificially sweetened or unsweetened alternatives over 12 months led to a reduction in body weight among individuals with central adiposity (11). The greater weight and fat loss observed in response to a low-sugar diet could be linked to a decrease in the secretion of leptin, an appetite-suppressing hormone (11). This reduction in leptin levels stimulates osteoblasts in the bone through brain signaling, ultimately augmenting the secretion of uncarboxylated osteocalcin (ucOC), a hormone released by bone tissue that is associated with anti-diabetic and anti-obesity effects (13). Consequently, limiting the consumption of sugary beverages can assist individuals in adopting healthier dietary patterns and maintaining a healthy body weight (14, 15).

Brisk walking is a frequently adopted exercise regimen among adults aiming to control their body weight (16). In the case of overweight adults, engaging in brisk walking interventions carries a minimal risk of injury while proving highly effective in achieving weight loss and mitigating the risk of metabolic conditions, including diabetes (17, 18). A systematic review and meta-analysis have indicated that brisk walking can efficiently reduce body weight, waist circumference, and fat mass in individuals below 50 years of age who are dealing with obesity (19). Furthermore, moderate-intensity exercise has been demonstrated to stimulate the secretion of osteocalcin (OC), potentially contributing to an amelioration in serum glucose levels (20, 21).

The rationale for focusing on women specifically lies in the unique metabolic and hormonal differences that influence how they process, and store fat compared to men. Women tend to have a higher percentage of body fat and different fat distribution patterns, which are influenced by hormonal fluctuations related to the menstrual cycle, pregnancy, and menopause (22). These factors can affect energy balance and the risk of developing metabolic disorders. Furthermore, women, particularly those living alone, may experience higher level of stress and emotional eating, leading to increased consumption of sugary snacks and beverages as coping mechanisms (23). By addressing these specific needs, our study aims to provide tailored interventions that can more effectively support women in managing their weight and improving metabolic health. Previous research has highlighted the success of gender-specific approaches in dietary and exercise interventions, suggesting that such strategies can yield better outcomes by considering the unique physiological and psychological needs of women (24–26).

To the best of our understanding, there has been no prior exploration into whether implementing a management program focused on restricting sugar-rich snacks and beverages could augment the benefits of a brisk walking exercise regimen on metabolic outcomes within overweight populations. This study comes at a critical time when the demand and need for effective lifestyle programs are on the rise for overweight management in Korea, reflecting a growing public health concern (27). Consequently, this study aims to examine the impact of limiting sugar-rich snacks and beverages on glucose metabolism markers and body composition among young women who are overweight and engaging in a non-face-to-face brisk walking program during the COVID-19 pandemic.

Sugar restriction, characterized by the limitation of sugar-rich snacks and beverages over an 8-week program and combined with non-face-to-face brisk walking exercise, led to additional improvements in body composition parameters. These parameters included body weight, body fat mass, percent body fat, and waist circumference, in comparison to the results seen in the group that only engaged in brisk walking. These findings suggest that the combination of nutritional intervention and exercise proves effective for weight management in young overweight women aged 20–39 living alone. However, contrary to our primary hypothesis, the nutritional intervention did not result in additional enhancements in glucose metabolism biomarkers.

A substantial body of research consistently suggests that brisk walking presents a viable strategy for promoting weight loss among young women in their 20s and 30s. Additionally, emerging evidence indicates that brisk walking may have favorable effects on lipid profiles (20). In this study, the exercise and control group experienced significant reductions in key measures, including body weight (1.8 ± 1.8 kg), and percent body fat (1.6 ± 1.7%). These findings align with our initial hypothesis and are in line with previous research outcomes. In a sedentary population of overweight women aged 21–30, engaging in in-person brisk walking for 45 min, five times a week, over 10 weeks led to significant weight reduction (17). Similarly, among sedentary young adults aged 20–40 who participated in 30 min of daily in-person walking exercise for 8 weeks, there was a notable reduction in percent body fat by (p < 0.05) (36).

Furthermore, physical activity represents a vital lifestyle intervention that has demonstrated its efficacy in improving glucose metabolism and reducing the risk of overweight. In this study, the exercise and control group exhibited significant decreases in fasting glucose by 9.2%, insulin by 30.5%, and HOMA-IR by 38.7%. These findings are consistent with prior research, confirming the favorable impact of exercise interventions on glucose metabolism biomarkers. According to Sandvei et al. (37), young adults engaging in continuous moderate-intensity aerobic training three times a week for 8 weeks at an intensity of 70–80% of maximal heart rate experienced a significant reduction in fasting glucose levels by 3.6%. Moreover, in obese young adults, insulin levels decreased by 45.4% following the eight-week aerobic exercise program (38). Remarkably, even though brisk walking was conducted in a non-face-to-face manner over 8 weeks in this study when compared to previous studies conducted in a face-to-face setting, it was observed that fasting glucose levels decreased to a greater extent, and insulin levels also decreased significantly, albeit not to the same extent as in the face-to-face program. This suggests that in the future, leveraging advanced devices and technologies for non-face-to-face brisk walking exercises could be an effective approach for improving glucose metabolism biomarkers in young obese women.

Our 8-week program, focusing on restricting sugar-rich snacks and beverages to reduce carbohydrate intake, resulted in notable improvements in body composition. While both groups experienced significant decreases in various body composition parameters, it is crucial to emphasize that the exercise and nutrition group achieved substantially greater reductions compared to the exercise and control group. Specifically, the exercise and nutrition group exhibited significant decreases in body weight, body fat mass, percent body fat, and waist circumference. In contrast, the exercise and control group showed reductions of a lesser magnitude, including decreases in body weight, body fat mass, percent body fat, and waist circumference. Previous reviews underscore the importance of reducing sugar-rich snack and beverage consumption as a complementary strategy for maintaining a healthy weight and promoting overall healthy dietary patterns (14, 15). A meta-analysis revealed that substituting sugar-sweetened beverages with low- or no-calorie sweetened alternatives was associated with weight reductions with a mean difference of −1.06 (−1.71 to −0.41 kg) (39), aligning with our study’s observation of a significantly greater reduction in body weight in the exercise and nutrition group that restricted their consumption of sugar-rich snacks and beverages compared to the exercise and control group. From a public health perspective, the integration of brisk walking with the reduction of sugar-rich snack and beverage consumption emerges as a straightforward and effective approach to facilitate weight loss and enhance overall well-being. Nevertheless, the widespread implementation of these interventions may necessitate policy modifications or environmental enhancements, including the provision of safe and walkable spaces or the implementation of taxes on sugar-sweetened beverages (40).

The exercise and nutrition group exhibited a notable reduction in fasting glucose levels (8.4 ± 10.9 mg/dL) following the 8-week intervention. However, no significant difference in the changes in fasting glucose was observed when compared to the exercise and control group. These outcomes suggest that there was no significant additional effect on glucose metabolism biomarkers when combining an exercise program with a nutrition program. Notably, the participants in this study did not display markedly elevated values for diabetes-related variables, particularly fasting glucose (98.9 ± 14.3 mg/dL) before the intervention. Therefore, despite the evident effectiveness of limiting the consumption of sugar-rich snacks and beverages in improving body composition, no substantial changes were observed in glucose metabolism. Moreover, it is important to acknowledge that the intervention period lasted only 8 weeks, which may have been insufficient to induce significant alterations in glycemic control indicators and other metabolic health parameters, especially among individuals whose initial glycemic profiles fell within the normal physiological range. Furthermore, lifestyle factors can exert a significant influence on glucose metabolism. One possible contributing factor is the timing and frequency of meals and snacks within individuals’ daily routines. In the case of single-person households in Korea, dining alone is common due to living arrangements, resulting in inconsistent mealtime and eating patterns (41).

In addition, while our study highlights the benefits of brisk walking combined with nutritional interventions for improving body composition and glucose metabolism, it is important to acknowledge the potential of other exercise forms. Resistance training, for example, has been demonstrated to also offer significant benefits in the improvement of glucose metabolism and body composition (42, 43). This suggests that integrating diverse forms of physical activity could further enhance the efficacy of lifestyles interventions targeted at metabolic health improvements. Such findings advocate for a broader inclusion of varied exercise modalities in future studies, potentially offering a more comprehensive approach to managing and improving metabolic health in similar populations.

The current study is subject to several limitations. Firstly, we did not implement controls to monitor participants’ sleep patterns or collect corresponding sleep-related data. Sleep quality and duration significantly impact various aspects of health, including glucose metabolism and overall energy levels. Individual variations in sleep patterns, such as inadequate sleep, irregular sleep schedules, or sleep disruptions, could introduce confounding variables influencing the study’s outcomes. The second limitation of our study is the small sample size, which was significantly influenced by external factors beyond our control, primarily the COVID-19 pandemic. The pandemic and the consequent social distancing measures imposed severe recruitment challenges. Many potential participants were hesitant to engage in a study involving physical visits during this period. Furthermore, there were several instances of participant dropouts due to COVID-19 infections and related concerns, which compounded the difficulty of maintaining a larger, stable cohort. To address this limitation and enhance the robustness of future studies, we recommend adopting more flexible and resilient recruitment and data collection methods that can adapt to similar disruptions. Thirdly, our examination of participants’ carbohydrate intake, as presented in Table 3, did not specifically measure sugar intake. In this study, an analysis of sugar intake was excluded from our assessment due to limitations in the nutrient analysis program used. Although this limitation prevents us from offering comprehensive insights into sugar consumption patterns, we believe that our study still provides valuable insights into other dietary components. Notably, the ExN group showed a significant reduction in carbohydrate intake between the week 0 and week 8, which includes sugars, suggesting that the observed effects could be partially attributed to reduced sugar consumption. While we cannot directly attribute the effects to sugar alone, the reduction in total carbohydrate intake likely reflects a decrease in sugar-rich foods. Future studies should include more detailed dietary assessments to differentiate the specific contributions of sugar reduction versus overall carbohydrate reduction This distinction is essential for developing more targeted and effective dietary strategies for weight management in young overweight women.

Our results indicate that a program focused on restricting the consumption of sugar-rich snacks and beverages may serve as a viable approach within diet-exercise strategies to promote weight loss among young women who are overweight or obese. These findings underscore the promise of implementing non-face-to-face nutrition and exercise behavioral programs in clinical practice, aiming to address overweight in young adult women living in single-person households. Future research is warranted to validate our observations, explore the long-term effects, and assess the feasibility of these non-face-to-face interventions by employing extended intervention durations.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving humans were approved by Korea University Institutional Review Board of the Korea (reference number: KUIRB-2021-0146-01). The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

YL: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Writing – original draft, Writing – review & editing. NK: Data curation, Formal analysis, Software, Validation, Visualization, Writing – review & editing. SG: Data curation, Investigation, Methodology, Writing – review & editing. JK: Conceptualization, Funding acquisition, Project administration, Resources, Supervision, Writing – review & editing. JP: Conceptualization, Funding acquisition, Project administration, Resources, Supervision, Validation, Writing – review & editing.