Introduction: Metabolic-associated fatty liver disease (MAFLD) represents a growing global problem and is associated with increasing obesity prevalence. Lifestyle modifications are the currently recommended approaches for MAFLD. Fibroscan device/transient elastography may be used to estimate the degree of liver scarring and steatosis using a controlled attenuation parameter (CAP) value. This study evaluated the short-term effect of lifestyle modifications on transient elastography values in an obese population with MAFLD. Methods: Thirty-two MAFLD patients aged between 18-60 years old who had a body mass index (BMI) of ≧23 kg/m2 with evidence of fatty liver disease by abdominal ultrasound were recruited for this prospective study. All subjects participated in a 3-month program of lifestyle modification. Sequential demographic parameters and biochemical tests were compared before and after program completion. Liver fat and fibrosis changes were measured using transient elastography with CAP and liver stiffness measurements (LSM). Results: The mean age was 38.7 years old. The body weight (88.09 kg vs. 80.35 kg), body mass index (32.24 kg/m2 vs. 29.4 kg/m2), waist (103.19 cm vs. 95.75 cm) and hip circumference (111.67 cm vs. 104.75 cm), and blood pressure (128/78 mmHg vs. 119/71 mmHg) significantly improved after intervention. Aspartate aminotransaminase (24.06 U/L vs. 18.91 U/L), alanine aminotransaminase (33 U/L vs. 23.72 U/L), creatinine (0.75 mg/dL vs. 0.70 mg/dL), cholesterol (176.41 mg/dL vs. 166.22 m/dL), gamma-glutamyl transferase (26.59 IU/L vs. 19.81 IU/L), and low-density lipoprotein cholesterol (115.63 mg/dL vs. 103.19 mg/dL) also improved after the 3-month intervention. The average CAP significantly decreased after intervention (297.5 dB/m vs. 255.0 dB/m), however, no significant difference in LSM was observed (5.24 kPa vs. 4.82 kPa) after intervention. (Figure) Conclusion: This study demonstrated that liver fat, assessed by CAP score, significantly reduced after a 3-month structured lifestyle modification program in patients with MAFLD. In addition, weight reduction, which is the major determining factor for MALFD improvement and/or resolution, was achieved with the structured program, and the CAP value may be used to monitor liver steatosis and respond to intervention. It is believed that this is the first study that evaluates the utility of CAP values for monitoring hepatic steatosis in an obese population with MAFLD through exercise and diet modification. (Table)Figure 1.: Controlled Attenuation Parameter (CAP) and Liver Stiffness (LSM) values before and after intervention. Table 1. - Comparison of Parameters and Biochemical Testing Before and After Intervention Pre-intervention Post-intervention Difference p-value Waist (cm) 103.19±13.12 95.75 ± 11.96 -7.44 ± 3.72 < 0.001 Hip (cm) 111.67 ± 10.72 104.75 ± 10.55 -6.92 ± 3.27 < 0.001 Weight (kg) 88.09 ± 20.75 80.35 ± 19.51 -7.74 ± 3.97 < 0.001 WHR 0.92 ± 0.06 0.91 ± 0.05 -0.01 ± 0.02 0.026 Body Fat (%) 37.07 ± 4.18 34.27 ± 4.44 -2.8 ± 1.44 < 0.001 BMI (kg/m2) 32.24 ± 4.98 29.4 ± 4.72 -2.84 ± 1.35 < 0.001 SBP (mmHg) 127.66 ± 15.57 119.09 ± 12.02 -8.56 ± 10.61 < 0.001 DBP (mmHg) 78.03 ± 13.58 71.09 ± 8.29 -6.94 ± 13.23 0.006 Heart rate (BPM) 84.5 ± 11.45 76.03 ± 10.91 -8.47 ± 12.06 < 0.001 HbA1c (%) 5.44 ± 0.54 5.47 ± 0.36 0.03 ± 0.33 0.67 Fasting Glucose (mg/dL) 89.44 ± 8.06 92.22 ± 7.56 2.78 ± 6.59 0.023 AST (U/L) 24.06 ± 8.85 18.91 ± 6.4 -5.16 ± 8.76 0.002 ALT (U/L) 33 ± 20.76 23.72 ± 14.72 -9.28 ± 19.79 0.012 GGT (IU/L) 26.59 ± 18.23 19.81 ± 14.83 -6.78 ± 10.05 0.001 BUN (mg/dL) 11.09 ± 2.23 11.31 ± 2.29 0.22 ± 2.55 0.631 Creatinine (mg/dL) 0.75 ± 0.17 0.70 ± 0.14 -0.05 ± 0.08 0.002 Chol (mg/dL) 176.41 ± 31.32 166.22 ± 32.13 -10.19 ± 24.14 0.023 TG (mg/dL) 122.59 ± 49.11 113.28 ± 61.32 -9.31 ± 46.8 0.269 HDL (mg/dL) 42.88 ± 8.29 43.94 ± 8.86 1.06 ± 4.99 0.238 LDL (mg/dL) 115.63 ± 28.03 103.19 ± 29.83 -12.44 ± 20.59 0.002 HOMA-IR (mg/dL) 2.65 ± 1.61 2.45 ± 1.85 -0.2 ± 1.94 0.564 WHR, waist-hip ratio; BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; BPM, beats per minute. HbA1c, hemoglobin A1c; AST, aspartate aminotransferase; ALT, alanine aminotransferase; GGT, gamma-glutamyl transferase; BUN, blood urea nitrogen; Chol, total cholesterol; TG, triglyceride; HDL, high-density lipoprotein; LDL, low-density lipoprotein; HOMA-IR, Homeostatic Model Assessment for Insulin Resistance.