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Low-carb superior to low-fat diet for hepatic fat loss regardless of NAFLD

Patients who followed a Mediterranean low-carbohydrate diet showed significant reductions in hepatic fat content beyond visceral adipose tissue changes that correlated with improvements in cardiometabolic parameters, according to a study published in Journal of Hepatology.

“Previous studies have demonstrated the inter-relationship between [visceral adipose tissue (VAT)] and hepatic fat content (HFC), and indeed, increases in HFC were associated with similar metabolic abnormalities as observed for increases in VAT,” Yftach Gepner, PhD, from the Ben-Gurion University of the Negev in Israel, and colleagues wrote. To verify this relationship, the researchers sought to test which diet would best induce HFC loss independently of VAT.

Gepner and colleagues randomly assigned 238 patients 1:1 to follow a low-fat diet or a Mediterranean low-carbohydrate diet for 6 months, followed by further randomization to add physical activity or no assigned physical activity to their dietary intervention for another 12 months.

Participants had an average BMI of 30.8 kg/m², 10.2% hepatic fat (range, 0.1%-50.4%), 53% had nonalcoholic fatty liver disease, 40% met the criteria for metabolic syndrome, 7% had abnormal waist circumference, and 11% had diabetes.

HFC decreased by 6.6% absolute unites and 41% relative units after 6 months in the entire cohort and by 4% absolute units and 29% relative units after 18 months (P < .001), along with 5.8% body weight loss at 6 months and 3.1% loss at 18 months.

After adjusting for VAT changes, the researchers observed more HFC reductions in patients following the Mediterranean diet after 18 months compared with the low-fat diet (–4.2% vs. –3.8; P = .036). The benefit of the Mediterranean diet was apparent in both patients with NAFLD (P = .014) and those without NAFLD (P = .037).

Gepner and colleagues noted that there were no significant differences between the physical activity groups during the second tier of the study with or without adjusting for VAT changes.

After further adjustment for age, sex, intervention group, and VAT changes, reduction of HFC remained independently associated with reduced gamma-glutamyl transferase (beta = 0.33; 95% CI, 0.24-0.42), alanine aminotransferase (beta = 0.189; 95% CI, 0.04-0.35) and chemerin (beta = 0.382; 95% CI ,0.23-0.53).

The Mediterranean diet induced a higher increase in HDL cholesterol (3.3 vs. 5.6 mg/dL) and greater decrease in diastolic blood pressure (1.2 vs. –1.9 mmHg), triglycerides (–3.4 vs. –10.8 mg/dL), and cardiovascular risk (P < .05) compared with the low-fat diet.

“This sub-study demonstrates how different weight loss strategies may induce favorable dynamics of HFC and consequently improve cardio-metabolic risk,” Gepner and colleagues concluded. “We suggest that improvements in specific easily-tracked blood biomarkers and cardiovascular risk associated with a decrease in HFC, beyond the loss of VAT. Thus, rather than focusing on weight loss only, our findings suggest that [low-carbohydrate Mediterranean] dietary intervention may be used as a specific approach for the management of NAFLD.” – by Talitha Bennett

Disclosure: The authors report no relevant financial disclosures.