There is more and more evidence linking fat deposition in the liver with metabolic dysfunctions. It is also reported that weight loss significantly improves hepatic steatosis. This paper reviews the available data concerning the effects of exercise on liver fat and discusses factors that may modulate exercise-induced changes in intrahepatic triglyceride (IHTG). Several studies have found that regular exercise was inversely associated with liver fat, and that this effect appeared to be secondary to the well-established exercise-induced reduction in intra-abdominal (visceral) fat. It was also reported that liver fat is quite labile in response to changes in energy balance and weight loss or decrease in intra-abdominal fat mass do not appear to be necessary for IHTG depletion to manifest, but they do increase the degree of IHTG depletion. Two intervention studies both indicated that the exercise-induced decrease in IHTG reaches a plateau. Exercise training reduces IHTG by limiting hepatic fatty acid uptake from the circulation and maybe favouring fatty acid disposal (oxidation and ketogenesis) over de novo synthesis. The effect of exercise on liver fat appears to be modulated by factors such as baseline IHTG, sex, type and volume of exercise, duration of training, diet, prandial status and the time elapsed from exercise cessation. Thus, further studies should be undertaken to examine all these factors and better understand the effect of exercise on hepatic steatosis.
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