Exercise, glucose control and liver fat :providing the evidence for translation into clinical care

Abstract

Non-alcoholic fatty liver disease (NAFLD) has become the most common form of liver disease throughout much of the World. It affects between one in five and one in three adults in the general population. It is now believed to be the leading cause of liver cirrhosis and hepatocellular carcinoma. However, the majority of people with NAFLD do not go on to develop terminal liver disease but instead have an uncertain prognosis that can often include type 2 diabetes, cardiovascular disease, and/or non-hepatic cancers. Indeed, NAFLD is frequently accompanied impaired glucose control, and almost always suboptimal insulin sensitivity. This thesis explores the only currently recommended therapy – weight reduction by lifestyle modification. It reviews the published evidence supporting this recommendation by applying a systematic approach to review the literature, but examines the findings in the broader context of common NAFLD comorbidities and sequelae. It also examines interaction of age and physical activity with liver fat, specifically in women, using both primary and secondary research methods. Finally, it explores exercise, particularly high-intensity intermittent training as a means to reduce liver fat, improve body composition, and attenuate insulin resistance independent of weight change and dietary advice. The principle finding is that, although the literature supports the recommendation of weight reduction, exercise can be an effective therapy to reduce liver fat and improve glucose control/insulin independent of weight change in adults with NAFLD. High-intensity intermittent training is particularly ii effective for liver fat reduction, improves glucose control/insulin resistance, and results in positive changes to body composition.