The global prevalence of overweight and obesity continues to rise, having become a major factor threatening public health. Recent WHO estimates indicate that in 2022, 2.5 billion adults (43%) were overweight, including 890 million living with obesity (16%), and adult obesity has more than doubled since 1990 (World Health Organization, 2025). Research shows that overweight status is often accompanied by insulin resistance, dyslipidemia, and other metabolic disorders, and is closely related to the occurrence of joint degeneration and musculoskeletal system diseases (Zhang et al., 2025). Elevated body mass index and circumferential measurements are often neglected in young and middle-aged populations, but may subsequently develop into serious chronic diseases (Chen et al., 2025). In order to encourage earlier intervention in overweight populations and obtain safe, feasible weight management plans, more pragmatic research is needed at both clinical and community levels. Diet control and exercise intervention are common weight loss strategies, but some patients fail to achieve stable effects due to lifestyle or adherence issues (Rabi Bazaz et al., 2025; Santisteban et al., 2024). Polysaccharides have shown potential in regulating blood glucose and lipids, improving intestinal microecology, and reducing fat absorption, among which chitosan has attracted widespread attention due to its high safety and tolerance (Feizolahi et al., 2024). With the help of systematic exercise prescriptions, polysaccharides may enhance metabolic efficiency and synergistically reduce cardiovascular and bone-joint burdens (Bajaber et al., 2024; Wong et al., 2024). However, the actual effectiveness and feasibility of polysaccharide-exercise synergistic interventions need to be verified by more rigorous research designs. Existing literature has reported certain improvements in metabolic indicators such as blood glucose and lipids under polysaccharide interventions (Nadhir et al., 2023), but there is a lack of in-depth discussion on their effects on lower limb biomechanical characteristics and exercise function. Clinically, overweight populations often face lower limb joint pain and structural damage as they age, while simplified or blind exercise plans may increase joint burdens (Lebenstei et al., 2023; Fatahi et al., 2022). How to regulate metabolism while also taking joint health into account is an urgent clinical challenge. Appropriate intensity, reasonable nutritional supplementation, and comprehensive adherence management may become a new direction for comprehensive intervention in this population. Based on the design concept of a randomized controlled trial, this study evaluated the effects of chitosan-assisted moderate-intensity exercise on body weight, fat distribution, metabolic indicators, and lower-limb biomechanical characteristics. To enhance interpretability between metabolic management and functional improvements, we adopted a multi-indicator assessment across body composition, glucose–lipid profiles, and joint mechanics. We hypothesized that, compared with an exercise-only program and with usual lifestyle, adding chitosan would produce greater improvements in metabolic regulation and reductions in lower-limb mechanical load over 12 weeks. The primary outcomes were the changes from baseline to Week 12 in fasting blood glucose and the homeostasis model assessment of insulin resistance (HOMA-IR). The goal of this study is to provide a safer, more feasible, and more effective comprehensive intervention plan for overweight individuals and, through systematic testing of body composition, blood glucose and lipid parameters, as well as joint mechanical indicators, to offer new evidence-based support for the application of polysaccharide-assisted exercise interventions in different age groups or in populations with specific comorbidities.

This study was a single-center, parallel-group, open-label randomized controlled trial (RCT) conducted at Zhejiang Industry Polytechnic College from March to December 2024. The protocol was approved by the Ethics Committee of Zhejiang Industry Polytechnic College, and all participants provided written informed consent. Participants and study staff were not blinded to group allocation.

This study shows that after a 12-week intervention, the combination of polysaccharides and moderate-intensity exercise led to a more pronounced decrease in body weight, BMI, waist circumference, hip circumference, and total body fat mass in overweight individuals. This result suggests that although exercise alone can improve body composition, the auxiliary role of polysaccharides may further enhance fat metabolism efficiency, thereby accelerating reductions in body fat and circumference. Chitosan and other polysaccharides in the gastrointestinal tract may inhibit the absorption of some fats and improve the body’s metabolic status by influencing gut flora and intestinal barrier function (Claire et al., 2022; Antonella et al., 2021). Moderate-intensity exercise plays a crucial role in negative energy balance and muscle energy metabolism, increasing energy consumption and activating aerobic metabolic pathways (Singh et al., 2021). On this basis, when both interventions occur simultaneously, the processes of fat breakdown and consumption may undergo a higher level of synergistic enhancement. Compared with exercise alone or not using polysaccharides, the dual intervention of polysaccharides plus exercise can more effectively alter the progression of abnormal body composition in overweight populations, which is of positive significance for weight management and may help prevent obesity-related chronic diseases. Previous research examining the combination of seaweed polysaccharides or soluble dietary fiber and exercise has also confirmed its positive effects on body fat control and circumference management (Liu et al., 2021), but the specific mechanisms still need further elucidation at the experimental and molecular levels. By integrating multiple indicators such as BMI, waist-hip circumference, and body fat mass, this study has, to some extent, demonstrated that polysaccharides can be incorporated as an auxiliary strategy into daily exercise prescriptions. In the future, conducting larger-scale studies among different age groups, varying degrees of obesity, or populations with comorbid metabolic diseases would be more conducive to clarifying the target groups and optimal intervention windows for this combined intervention model, potentially providing more practical and accessible intervention programs for clinical practice and public health.

This study found that, after combining polysaccharides with moderate-intensity exercise, there was a more pronounced improvement in indicators such as blood glucose, blood lipids, and HOMA-IR compared to the control group and the exercise-only group, suggesting that this composite intervention model has positive significance for enhancing the body’s metabolic regulation. These changes were statistically significant: the time × group interaction was significant for HOMA-IR (F = 6.109, P = 0.004), triglycerides (TG) (F = 5.348, P = 0.007), and LDL-C (F = 4.235, P = 0.021), with Bonferroni-corrected post-hoc tests showing greater improvements at T12 in the chitosan-plus-exercise group than in both comparison groups (all P < 0.05). Polysaccharides may bind cholesterol and free fatty acids in the gastrointestinal tract, thereby reducing lipid absorption and blood lipid formation, while to some extent improving insulin sensitivity and thus alleviating insulin resistance (Chen et al., 2021). Moderate-intensity exercise brings a dual optimization of blood glucose and blood lipid levels by increasing energy expenditure, promoting mitochondrial oxidation, and enhancing the uptake and utilization of glucose and lipids by skeletal muscle (Wang et al., 2020). In addition, only glycated hemoglobin did not show obvious improvement after the intervention, which may be related to the relatively limited intervention duration or the fact that baseline glucose metabolism abnormalities in the subjects were not yet severe. This pattern is consistent with the biology of HbA1c, which reflects average glycemia over approximately 2–3 months and may lag behind shorter-term improvements (American Diabetes Association Professional Practice Committee et al., 2024). It also indicates that changes in long-term cumulative indicators of blood glucose may require a longer period to fully manifest (Molina-Garcia et al., 2019). From the perspective of preventing and slowing the progression of metabolic syndrome in overweight populations, the study results emphasize that a combined strategy of polysaccharides and exercise may provide a feasible option for early intervention. No severe adverse events were observed during the entire intervention, indicating that the safety and operability of this program are relatively assured in practical application. In the future, more centers and longer follow-up are needed to further explore the lasting effects of polysaccharides in maintaining stable blood glucose, reducing insulin resistance, and lowering blood lipids. More in-depth molecular and clinical research will also be necessary to clarify the mechanisms of action, thus providing a more solid evidence base for clinical application and health management.

Polysaccharide-assisted exercise has been further confirmed in this study to have a positive impact on lower limb biomechanical characteristics, with the polysaccharide + exercise group showing the most significant reduction in maximum plantar pressure, peak ground reaction force, and peak knee-ankle joint moments after the intervention. The decrease in body weight directly reduces lower limb loading, which is particularly evident in terms of foot-bearing pressure; the simultaneous reductions in maximum plantar pressure and peak ground reaction force indicate that exercise impact and joint stress have been alleviated to some extent. The decrease in total body fat mass reduces the mechanical load on joint cartilage, helping to optimize the distribution of lower limb force lines (Nagaoka et al., 2019). Meanwhile, the improvements in muscle strength and endurance brought about by the combined intervention of polysaccharides and moderate-intensity exercise enable better muscular support and neuromuscular control for the major joints such as the knee and ankle when bearing weight, making the gait more stable and thereby lowering joint moments. This further highlights the synergistic effect between reduced body fat and enhanced muscle function (Silva et al., 2018). Unlike exercise alone or dietary intervention alone, this polysaccharide-assisted approach not only promotes a negative energy balance but also helps some subjects maintain their fat-free mass during sustained exercise, preventing substantial muscle loss (Chen et al., 2024). When the joints are in motion and have better muscular protection, the areas of pressure concentration under the foot and in the joints can be dispersed, thereby reducing the potential risk of exercise-related injuries or chronic joint degeneration. For overweight or mildly obese populations, this composite intervention that combines weight management with a basic exercise prescription is of practical significance. The direction of these changes is consistent with current physical activity and weight-management guidance, which recommends at least 150 min per week of moderate-intensity aerobic activity alongside multicomponent programs that include muscle-strengthening and balance/neuromotor training; our findings extend these recommendations by suggesting that pairing such aerobic exercise with chitosan may further lower mechanical loading and improve functional indices. Under conditions of adequate resources and higher adherence, incorporating strength or balance training into a polysaccharide-assisted system may yield even more significant improvements in exercise function. However, this should be framed as a hypothesis for future, adequately powered trials rather than as a conclusion of the present study. In clinical practice, corresponding polysaccharide and exercise prescriptions can be matched to population characteristics and exercise preferences, striving to enhance safety and adherence through individualized design, and ultimately form an effective plan for weight reduction and joint function maintenance. As the sample size expands and follow-up extends over a longer period, the value of this composite intervention in preventing lower limb osteoarticular lesions and preserving daily physical activity will be further evidenced, providing more feasible options for patients with obesity combined with joint problems.

The primary limitations of this study include the relatively small sample size, short follow-up duration of 12 weeks, and open-label trial design without placebo capsules for the exercise-only and control groups. The absence of blinding and placebo control may introduce performance and expectancy bias, such as behavioral changes or varying adherence, potentially influencing between-group comparisons despite most outcomes being objectively assessed (e.g., DXA, automated biochemical assays, and biomechanical measurements). Free-living physical activity outside the intervention sessions was not monitored, leaving the possibility that unmeasured incidental activity contributed to greater improvements in the polysaccharide-plus-exercise group. Future studies should incorporate accelerometry or step tracking to account for habitual activity levels. Multicenter trials with participant and assessor blinding, use of appearance-matched placebos, and extended follow-up periods would enhance internal validity and the generalizability of the findings. Although the positive effects of combining polysaccharides with exercise on metabolic and lower limb biomechanical indicators in overweight populations were preliminarily observed, it remains uncertain whether these effects can be sustained over the long term. In particular, some long-term indicators related to metabolic syndrome, such as glycated hemoglobin, did not show significant improvement in the short term, suggesting that future research should consider a longer follow-up period to determine the long-term metabolic benefits and sustainability of polysaccharide-assisted exercise. Although the overall intervention adherence rate was relatively high, there may be a risk of declining adherence in actual promotion and application, especially among community populations lacking effective supervision methods. This highlights the need to further explore specific strategies to improve long-term adherence. Potential solutions include wearable- or app-based remote monitoring with automated reminders and individualized feedback, brief telecoaching contacts, and community-based group programs to provide peer support and accountability. In addition, this study only included overweight adults, and future research should be expanded to include obese or clinically patient populations with significant metabolic abnormalities to evaluate its clinical generalizability. We focused on overweight rather than obesity to test early-intervention feasibility while limiting musculoskeletal loading and injury risk during moderate-intensity activity and to minimize confounding from anti-obesity pharmacotherapy or mobility limitations; the trial was not powered for age- or sex-stratified analyses, so applicability to older adults and sex-specific responses should be confirmed in larger studies. Regarding lower limb biomechanical assessment, this study was limited to basic gait analysis. In the future, dynamic exercise testing or joint imaging examinations could be added to more comprehensively elucidate the protective effects of polysaccharide-assisted exercise on joint structure and function. Furthermore, this study did not involve testing of the gut microbiota or metabolomics related to polysaccharides. Based on current evidence, we hypothesize that the combined intervention may act through microbiome-mediated pathways—such as increased short-chain fatty acid production, improved intestinal barrier integrity with reduced endotoxemia, and altered bile-acid signaling—thereby contributing to the observed improvements in insulin resistance and lipid profiles; future work should incorporate fecal metagenomics/metabolomics and SCFA/bile-acid profiling to test these mechanisms (Zhang et al., 2022).

The results of this study indicate that an intervention model combining polysaccharides with moderate-intensity exercise can significantly improve body composition, metabolic indicators, and lower limb biomechanical characteristics in overweight populations, and demonstrates better effects than exercise alone or the control group in reducing body weight, improving insulin resistance and blood lipid levels, and alleviating plantar and joint load. Polysaccharides such as chitosan, synergistically combined with regular exercise, can effectively promote fat metabolism, improve metabolic health, and exhibit good safety and adherence, suggesting that this composite intervention program could serve as one of the effective strategies for managing overweight individuals.