Nonalcoholic fatty liver disease (NAFLD), now termed metabolic dysfunction-associated steatotic liver disease (MASLD), is a prevalent liver disease linked to excessive hepatic fat accumulation without excessive alcohol consumption. MASLD is strongly associated with obesity, metabolic syndrome, hypertension, and diabetes. Lifestyle interventions, including weight loss, are crucial for management. Modern life often necessitates faster mealtimes, but the association between fast eating and metabolic diseases, including MASLD, remains unclear. While some studies suggest a link between fast eating and increased risk of MASLD, others find no significant association. This study aimed to clarify this relationship through a large-scale multicenter cross-sectional study in China and a subsequent meta-analysis of existing literature.

Previous research on the relationship between fast eating and MASLD has yielded mixed results. Some studies reported a positive correlation between fast eating and the prevalence of MASLD, particularly in specific populations like Korean adults and male diabetic patients. These studies observed that individuals who ate quickly had a higher likelihood of developing MASLD. However, other studies found no independent association between fast eating and MASLD risk after adjusting for factors such as body mass index (BMI) and waist circumference. The inconsistency across these studies highlights the need for a larger, more comprehensive investigation to determine the true nature of this relationship.

This research comprised a multicenter cross-sectional study and a meta-analysis. The cross-sectional study enrolled 1965 participants from 10 clinics across six Chinese provinces/municipalities. Fast eating was defined as consuming a meal in under five minutes, with participants categorized into three frequency groups: ≤1 time/month, ≤1 time/week, and ≥2 times/week. Data collected included demographics, lifestyle factors (smoking, alcohol consumption), anthropometric measurements (BMI, waist circumference), and blood biochemistry (lipids, liver enzymes, glucose levels). MASLD was diagnosed via ultrasonography. Multivariable logistic regression was used to analyze the association between fast eating frequency and MASLD risk, adjusting for potential confounders. The meta-analysis searched PubMed and Web of Science for relevant studies published before November 2023. Eligible studies were those that presented odds ratios (ORs) or relative risks (RRs) linking eating speed and MASLD risk. A random-effects model was used to pool the results, and heterogeneity was assessed using I² and τ². The Newcastle-Ottawa Scale (NOS) and Agency for Healthcare Research and Quality (AHRQ) scale assessed the quality of included studies.

The cross-sectional study revealed a significant association between frequent fast eating and MASLD. The proportion of participants with MASLD increased with faster eating frequency (46.2%, 50.5%, and 59.3% for ≤1 time/month, ≤1 time/week, and ≥2 times/week, respectively, P for trend <0.001). After multivariable adjustment for demographic, lifestyle, and metabolic factors, frequent fast eating (≥2 times/week) was independently associated with an 81% higher risk of MASLD (OR, 1.81; 95%CI, 1.26–2.59). The meta-analysis, including four eligible studies and the current study’s data, confirmed this association, showing a pooled OR of 1.22 (95%CI: 1.07–1.39) for frequent fast eating and MASLD risk. Subgroup analyses showed a significant association in women, non-smokers, northern residents, those with impaired glucose regulation (IGR), and those with BMI <25 kg/m². No significant interactions were found between fast eating and major risk factors.

This study's findings strongly suggest an independent association between frequent fast eating and increased MASLD risk. While the exact mechanisms remain to be fully elucidated, several possibilities exist. Fast eating may lead to excessive energy intake, weight gain, and subsequent MASLD development. It may also affect gut hormone responses, potentially leading to increased appetite and further energy intake. Although some previous studies showed that the association disappeared after adjusting for BMI and calorie intake, this study's findings, even after adjusting for various confounding factors, suggest a direct effect of fast eating on liver lipid metabolism, possibly through the gut-liver-adipose axis. The impact on gut hormone levels (ghrelin, GLP-1, PYY) and their interaction with the gut microbiota could play a role. However, more research is needed to confirm these pathways.

This large-scale multicenter study and meta-analysis provide strong evidence for an independent association between frequent fast eating and increased MASLD risk. Future research should investigate the underlying mechanisms, explore the relationship between eating speed and liver fibrosis, and evaluate whether improving eating habits can positively influence MASLD development.

This study's cross-sectional design limits the ability to establish causality. The study primarily included participants of Asian descent, potentially limiting the generalizability of the findings to other populations. The lack of detailed dietary information, including energy intake and macronutrient composition, is a limitation. The definition of "fast eating" varied across studies included in the meta-analysis, potentially introducing heterogeneity.