Ketogenic diets and metabolic dysfunction-associated steatotic liver disease: a literature review

Metabolic dysfunction-associated steatotic liver disease (MASLD) is estimated to affect over 30% of the global population with a rising trend, posing significant healthcare burden due to its progression and increased risk of related metabolic diseases. Dietary intervention plays an important role in the prevention and management of MASLD. Ketogenic diets represent a range of high-fat, moderate-protein, very low-carbohydrate (< 20-50 g/day) diets that induce nutritional ketosis. These diets have been proposed to benefit patients with MASLD by promoting weight loss, reducing inflammation and insulin resistance through different pathways. This review summarized the current findings on the outcomes of ketogenic diets on patients with MASLD regarding the liver, plasma lipid profile, systemic inflammation and gut microbiota. Studies showed that short- to medium- term ketogenic diets, with or without calorie restriction, are able to lower plasma triglycerides and ameliorate hepatic steatosis, steatohepatitis and fibrosis in MASLD. In particular, studies found ketogenic diets may be more effective in alleviating hepatic steatosis in short time periods than calorie-matched, high-carbohydrate, low-fat diets. Evidence on the impact on plasma high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c) was mixed. Clinical trials investigating the effects on different markers of systemic inflammation and the composition of gut microbiota among patients with MASLD were scarce. To better understand the role of ketogenic diets in MASLD management, longer-term, well-controlled trials are warranted to clarify their potential benefits and risks, and whether they are varied by types of fats. Appropriate and sustainable formulations of ketogenic diets that maximize benefits and minimize side effects remain to be determined.