Introduction: Nonalcoholic Fatty Liver Disease (NAFLD) has become the leading cause of liver morbidity. The Mediterranean diet can improve NAFLD and may be offered as treatment. Intermittent fasting has been shown to improve aspects of the metabolic syndrome, but its effect on NAFLD is inconclusive.
Objectives: A randomized - controlled study assessed the outcomes of the effect of the Mediterranean diet alone versus the Mediterranean diet in combination with intermittent fasting for 16 weeks in patients with NAFLD (1:2 ratio) and subsequent long term follow-up. Outcomes parameters included the response to treatment as measured by body mass index (height and weight), waist-hip ratio, and levels of steatosis and fibrosis as measured by transient elastography. In addition, satisfaction and compliance were assessed via questionnaires (ten-point Likert scale).
Results: Sixteen out of 40 recruited patients completed the study (69% men, mean age 45.8 ± 12.1 years, mean baseline BMI 33 ± 4.5), of which nine patients were included in the arm of diet in combination with intermittent fasting. The two groups were similar at baseline with regard to age, gender, height, weight, BMI, waist to hip ratio, and levels of steatosis and fibrosis. At the study end, a significant decrease was observed (p-value = 0.01) in the degree of steatosis from 316.4 ± 50.4 to 279 ± 35.7 DB/m. The improvement in steatosis was significant (p-value = 0.01) in the intermittent fasting group (an improvement of 13.8 ± 20.9%) as compared to the group without intermittent fasting (4.2 ± 20.9%, no statistical significance). The other physical outcome measures did not show a statistically significant change between values at the beginning of the study and study end (16 weeks). Participant questionnaires were completed at a mean follow-up of 1.6 ± 0.2 years and showed a high level (8.3 ± 1.69) of compliance at the beginning of the study in both groups. In addition, both study groups expressed a similar degree of difficulty in adhering to the assigned diet. By study end, participant adherence was significantly higher (p-value = 0.04) among the Mediterranean diet group alone (7 ± 2) as compared to the group in combination with intermittent fasting (4.9 ± 2). Furthermore, those in the Mediterranean diet alone group were more willing (9.7 ± 0.8) to continue the dietary treatment after completing the study as compared to the intermittent fasting group (6.4 ± 0.7) (p-value = 0.03). Study participants in both groups reported that their dietary treatment was overall beneficial (7.9 ± 2.2).
Conclusions: This study, given the limitations of a small sample size, suggests that a Mediterranean diet in combination with intermittent fasting improves steatosis in NAFLD patients over the long term as compared to Mediterranean diet without time restricted eating.