In people with prediabetes or type 2 diabetes, a diet enriched in monounsaturated fat (22–28% of energy intake; primarily from olive oil) has been shown to reduce liver fat compared to a diet enriched in fiber and slightly higher in carbohydrates, independent of changes in body weight.[1][2] In addition, saturated fats have been shown to increase liver fat compared to polyunsaturated fats.[3][4][5][6]
Collectively, these findings indicate that unsaturated fat may have a positive effect on liver fat, especially compared to saturated fat. However, in each of these studies, body weight either did not change (the studies on monounsaturated fat) or increased (the studies on polyunsaturated fat).
A randomized controlled trial in participants with abdominal obesity found that a hypocaloric diet enriched in monounsaturated and polyunsaturated fat (13.4% and 7.7% of energy intake) and reduced in saturated fat (8.3% of energy intake) produced similar reductions in liver fat as a hypocaloric diet that was lower in monounsaturated and polyunsaturated fat (9.3% and 4.1% of energy intake) and higher in saturated fat (14.9% of energy intake).[7] Although it’s possible that the difference in unsaturated fat intake wasn’t large enough to produce significant differences in liver fat between groups, these findings suggest that the potent effects of energy restriction on liver fat far outweigh the effects of the type of fat consumed.