All groups will use the Xiangdong Health app for exercise prescriptions, self-monitoring, and behavioral feedback. The staple food reduction group will reduce staple food intake by approximately one half at three meals without restriction of eating time. The early time-restricted eating group will consume food only between 07:00 and 15:00, with water allowed outside the eating window, without prescribed restriction of total daily energy intake. Outcomes will be measured at baseline, week 12, and week 24, including body weight, glycemic indices, continuous glucose monitoring metrics, body composition, blood pressure, blood biochemistry, urine tests, stool microbiome, dietary recall, physical activity, sleep, appetite, psychological measures, adherence, and adverse events.
