The study involved 121 obese children and adolescents divided into a control group with a balanced diet and exercise and a study group with a low-carbohydrate, high-nutrient-dense diet combined with daily aerobic exercise (swimming, jogging, jumping rope, badminton, running or stair climbing, 30–60 minutes) for 8 weeks. After the intervention, the study group had lower BMI (17.56 ± 1.72 kg/m²), body fat content (101.75 ± 8 kg), body fat percentage (101.75 ± 3.82%), and waist-to-hip ratio (0.72 ± 0.07) compared to the control group (19.32 ± 2.01 kg/m², 19.02 ± 1.95 kg/m²). 41.78 ± 4.18%, 0.89 ± 0.09; p < 0.05). The study group had lower levels of total cholesterol (TC 4.06 ± 0.41 mmol/l), LDL-C (4.26 ± 0.43 mmol/l), triglycerides (TG 1.16 ± 0.17 mmol/l) and higher HDL-C compared to the control group (TC 5.91 ± 0.60 mmol/l, LDL-C 3.65 ± 0.36 mmol/l, TG 1.62 ± 0.16 mmol/l, HDL-C 1.38 ± 0.14 mmol/l; p < 0.05). Glucose metabolism improved in the study group with lower values of FPG (4.82 ± 0.48 mmol/l), C-peptide (5.18 ± 0.52 μU/ml), FINS (539 ± 2.1 pmol/l) and HOMA-IR (1.1 ± 0.11) compared to the control group (5.45 ± 0.55 mmol/l, 8.62 ± 0.86 μU/mL, 723.15 ± 72.35 pmol/L, 1.92 ± 0.19; p < 0.05). Scores of anxiety (SAS 36.28 ± 3.62 points) and depression (SDS 37.26 ± 2