Nonalcoholic fatty liver disease, characterized by elevated liver enzymes, central obesity, and insulin resistance, is becoming increasingly prevalent. The effects of changes in physical activity on the metabolic profile of this group have not been reported. We assessed at 3 months the impact of a behavior change-based lifestyle intervention on physical activity and the effects of this change on the metabolic profile of people with fatty liver disease. In all, 141 participants with nonalcoholic fatty liver disease were prospectively enrolled into either a low-or moderate-intensity lifestyle intervention or to a control group. Physical activity was assessed using a validated reporting tool and physical fitness was measured using the YMCA protocol on a cycle ergometer. Individualized counseling to increase physical activity was provided. Overall, 96% of participants attended the 3-month follow-up assessment. Participants in the moderate-and low-intensity intervention groups were 9 times more likely to increase physical activity by an hour or more per week compared to controls. Patients increasing or maintaining their reported physical activity to >150 minutes/week, and those who increased their objective levels of fitness, had the greatest improvements in liver enzymes and other metabolic indices compared to those who were least active. This effect was independent of weight loss and was corroborated by an objective measure of fitness. There was no dose-response effect on liver enzymes with incremental increases in physical activity above 60 minutes/week. Conclusion: Lifestyle counseling interventions are effective in improving physical activity behavior. Maintaining or increasing physical activity provides health benefits for patients with fatty liver, independent of changes in weight. (HEPATOLOGY 2009;50:68-76.)

Background and Aim: Non-alcoholic fatty liver disease associated with insulin resistance is the most common cause of abnormal liver tests in clinical practice. To date, practical and effective strategies to improve the metabolic profile of this large group of patients have not been well characterised. We sought to assess the effect at 3 months of a behavior changebased lifestyle intervention on the metabolic profile of patients characterised by elevated liver enzymes. Methods: A total of 152 patients with elevated liver enzymes, central obesity and a range of metabolic risk factors were randomised to either a moderate-(6 sessions/10 weeks) or low-intensity (3 sessions/4 weeks) lifestyle counselling intervention or control group. Results: There was improvement in all metabolic risk factors in the moderate-intensity group, versus a smaller number of changes in the low-intensity intervention group and no change in any metabolic risk factors in control subjects. Reduction in liver enzymes was greatest in the moderate-intensity intervention group and least in the control group. The likelihood of elevated alanine aminotransferase (ALT) levels in both the moderate and low-intensity groups was reduced by over 70% compared to controls. The proportion of subjects achieving weight loss (Ն 2%) was significantly higher in the moderate-intensity intervention group (66%) versus the low-intensity intervention group (39%; P < 0.05) and controls (29%; P < 0.001). Conclusions: Moderate and even low-intensity lifestyle counselling interventions targeting improvement in physical activity and nutritional behaviors and modest weight loss are a practical and effective method for improving the health of patients with elevated liver enzymes and a range of metabolic risk factors.