Which dietary patterns fend off nonalcoholic fatty liver disease? A systematic review of observational and interventional studies.

Background: The global burden of non-alcoholic fatty liver disease (NAFLD) has significantly risen over the past decade. Dietary intake strongly influences its development and should be a component of any prevention and treatment plan strategy. Dietary pattern analysis enables the investigation of the overall diet and permits the consideration of interactions and cumulative effects of dietary components. The current study aimed to systematically review observational studies and intervention trials to determine the associations between various dietary patterns and NAFLD.

Methods: The protocol was written according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched PubMed, Embase, and the Cochrane Library. We included studies that reported a priori dietary pattern (i.e., diet quality scores) or a posteriori method, which identified existing eating patterns (i.e., principal component analysis) in adult participants. Two investigators conducted independent screening, extraction, and quality assessment using the Newcastle‒Ottawa or Jadad scale. A third reviewer resolved conflicts.

Results: We identified 27 relevant observational and 16 interventional studies from 16 countries. A Mediterranean or DASH diet might prevent and improve NAFLD, whereas dietary patterns such as Western dietary patterns characterized by high consumption of sweets and animal foods such as red meat and fast food are positively associated with NAFLD. A low-carbohydrate diet effectively prevents and treats NAFLD; however, we need more research on the effects of a low-fat diet and the type of fats.

Conclusion: Healthy dietary patterns, mainly plant-based or adjusted macronutrient distributions, such as the adoption of a low-carbohydrate diet, are linked to a reduced risk of NAFLD and could halt its progression. We proposed recommendations for future studies to fill the gap in knowledge regarding the management of NAFLD via dietary modifications.