St George, A. et al. Independent effects of physical activity in patients with nonalcoholic fatty liver disease. Hepatology 50, 68–76 (2009).

Patients with nonalcoholic fatty liver disease (NAFLD) benefit from increased levels of physical activity—an effect that is independent of weight loss. “Increasing physical activity by an hour or more per week leads to significant improvements in risk factors for NAFLD”, Jacob George of the study group summarizes.

Patients with NAFLD are typically advised to lose weight through dietary change and increased physical activity. However, few studies have investigated the effects of lifestyle intervention in large groups of such patients. George explains, “...we [identified] a clear need to report on the effects of lifestyle change, in particular physical activity ... in patients with NAFLD”.

The researchers evaluated the effects of a counseling-based lifestyle intervention in 141 patients with NAFLD, which addressed the factors that affected each individual's ability to alter their dietary and physical behaviors. Physical activity was measured by use of self-reported data, and these data were corroborated by assessments of cardiorespiratory fitness. Patients who undertook the intervention program significantly increased their weekly physical activity. Moreover, liver enzyme levels and metabolic risk factors improved in those who increased their amount of physical activity by an hour or more each week. These changes were evident even in patients who undertook low-intensity activity, despite the absence of changes in body weight. The researchers also noted that inactivity was associated with a clear trend towards deterioration of several metabolic parameters. The researchers believe their findings demonstrate that significant increases in physical activity can be achieved with positive effects in patients with NAFLD without a need for structured, supervised exercise lessons. They now plan to look at the long term effects of interventional programs in patients with NAFLD.