In one study, obese adults who consumed a diet high in calories and refined carbs for three weeks experienced a 27% increase in liver fat, on average, even though their weight only increased by 2% ( 15 ).
Lose Weight and Avoid Overeating If Overweight or Obese.
What’s more, it appears that the improvements in liver fat and insulin sensitivity may persist even if some of the weight is regained ( 25 ).
Obesity: Obesity involves low-grade inflammation that may promote liver fat storage. It’s estimated that 30–90% of obese adults have NAFLD, and it’s increasing in children due to the childhood obesity epidemic ( 2 , 3 , 9 , 10 ). Excess belly fat: Normal-weight people may develop fatty liver if they are “viscerally obese,” meaning they carry too much fat around the waist ( 11 ). Insulin resistance: Insulin resistance and high insulin levels have been shown to increase liver fat storage in people with type 2 diabetes and metabolic syndrome ( 12 , 13 ). High intake of refined carbs: Frequent intake of refined carbs promotes liver fat storage, especially when high amounts are consumed by overweight or insulin-resistant individuals ( 14 , 15 ). Sugary beverage consumption: Sugar-sweetened beverages like soda and energy drinks are high in fructose, which has been shown to drive liver fat accumulation in children and adults ( 16 , 17 ). Impaired gut health: Recent research suggests that having an imbalance in gut bacteria, problems with gut barrier function (“leaky gut”) or other gut health issues may contribute to NAFLD development ( 18 , 19 ).
In this study, 14 obese men with NAFLD followed a Mediterranean ketogenic diet. After 12 weeks, 13 of the men experienced reductions in liver fat, including three who achieved complete resolution of fatty liver ( 31 ).
Unfortunately, it is difficult to predict whether fatty liver will progress to NASH, which greatly increases the risk of cirrhosis (severe scarring that impairs liver function) and liver cancer ( 4 , 5 ).
NAFLD is also linked to an increased risk of other diseases, including heart disease, diabetes and kidney disease ( 6 , 7 , 8 ).
NASH involves greater fat accumulation and inflammation that damages the liver cells. This can lead to fibrosis, or scar tissue, as liver cells are repeatedly injured and die off.