BACKGROUND

Lifestyle interventions are a critical component of weight loss programs, yet digital, personalized, and theory- and evidence-based lifestyle interventions remain limited.

OBJECTIVE

This study aimed to investigate the effects of a combination of various dietary approaches and digital technology-based exercise on the body composition of college students with obesity.

METHODS

A total of 129 college students with obesity (mean age 18.3, SD 0.7 years; mean weight 89.9, SD 13.6 kg; mean BMI 30.6, SD 3.3 kg/m) were initially recruited for this study. After excluding 2 participants, 127 students with obesity were ultimately included in the statistical analysis. An 8-week weight loss intervention was conducted with the students, combining exercise and various digitally supported dietary approaches. Body composition indicators (muscle mass and fat mass) were assessed before and after the intervention. Participants were divided into 3 experimental groups (twice-weekly fasting [TWF], low-calorie diet [LCD], and time-restricted feeding [TRF]). Between-group comparisons were made using a 1-way ANOVA, while within-group comparisons used a repeated-measures ANOVA. Linear mixed-effects models were used to examine the interaction effects between sex and time, as well as between sex and group.

RESULTS

All groups showed significant decreases in weight and BMI, and the TRF group also showed a significant decrease in BMI (P=.002), but there were significant sex differences. The male TWF group showed the largest decrease in weight (mean difference [MD] -4.86 kg; P<.001), BMI (MD -1.1 kg/m; P<.001), visceral fat mass (MD -0.607 kg; P=.003) and subcutaneous fat mass (MD -1.987 kg; P<.001) at 8 weeks. Improvements in weight (MD -5.662 kg; P<.001) and BMI (MD -1.587 kg/m; P<.001) were more pronounced in the LCD group of female participants (P<.001). Muscle mass declined significantly in male participants in the TRF group at 4 weeks (P<.001) but stabilized at 8 weeks (P=.87). Linear mixed effects models showed that the sex and diet interaction significantly affected subcutaneous fat mass (P=.02). The effect of TRF on muscle mass in male participants peaked at 4 weeks (P<.001), with no significant difference from the control group at 8 weeks (P=.91).

CONCLUSIONS

This study demonstrated that 3 diet-combined exercise regimens produced sex-specific improvements in body composition in college students with obesity. Male participants achieved maximum visceral fat mass loss after 8 weeks with TWF combined with exercise, whereas female participants achieved greater total body fat loss with LCD combined with exercise. The effectiveness of the closed-loop monitoring-feedback behavior modification was verified by digital technology through intelligent monitoring to improve dietary compliance and a real-time feedback mechanism to enhance the effect of the intervention. The sex and diet interaction significantly affected subcutaneous fat mass; women who used LCD and TRF needed additional protein supplementation. Digital technology shows great potential in obesity management and is worth promoting.