Very low-calorie ketogenic diet safe and beneficial for obese patients with NAFLD

The beneficial effect could be due to the simultaneous effects of different factors (commonly associated with NAFLD), such as the reduction of insulin resistance (IR), insulin levels, fat mass and body weight, and induction of ketosis.

This study, conducted on thirty-three subjects who were either obese or overweight and were not taking any kind of drug, revealed that an 8-week VLCKD (<800 kcal/day) might notably decrease liver fat accumulation.

"These results clearly show that carbohydrates restriction to less than 50 g/day usually leads to ketosis, produces a NAFLD improvement in line with the concept that the hepatoprotective role of carbohydrate restriction appears to be boosted when ketogenesis is induced and when there is a marked reduction in total calorie intake," the researchers wrote.

Lifestyle changes, more physical activity and a healthy diet are the cornerstones of NAFLD prevention. These adjustments lower systemic inflammation, enhance IR, reduce fat build-up, encourage weight loss and raise skeletal muscle mass.

Concerning the diet as therapy for body weight reduction, the ketogenic diet is now a popular weight loss intervention with its drastic carbohydrate reduction; in particular, a very-low-calorie ketogenic diet is considered an efficient and secure therapeutic intervention for people with obesity. In obese people, VLCKD is shown to induce several health effects, but more information is needed on the possible beneficial effects of VLCKD on NAFLD in these people.

Considering the lack of information on this topic, Roberta Rinaldi and colleagues from Italy evaluated the safety and efficacy of a VLCKD on NAFLD and parameters associated commonly with this condition in obese/overweight subjects who did not take any drugs in a prospective, real-life study.

The study included thirty-three participants who followed a very-low-calorie ketogenic diet for eight weeks. Data was gathered on bioimpedance analysis, anthropometric measurements, and biochemical assays before and after the dietary intervention. NAFLD diagnosis was made using transient elastography (FibroScan).

The study led to the following findings:

• After VLCKD, there was a significant reduction in BMI (kg/m2) (from 33.84 ± 6.55 to 30.89 ± 6.38), waist circumference (cm) (from 106.67 ± 15.51 to 98.64 ± 16.21), and fat mass (Kg) (from 38.47 ± 12.59 to 30.98 ± 12.39).
• CAP (controlled attenuation parameter; db/m), the FibroScan parameter quantifying fatty liver accumulation, significantly reduced after VLCKD (from 266.61 ± 67.96 to 223 ± 64.19).
• After VLCKD, the FLI (fatty liver index), a benchmark of steatosis, also showed a significant decline (from 62.82 ± 27.46 to 44.09 ± 31.24).
• Fasting blood glucose, triglycerides, insulin, total cholesterol, LDL-cholesterol, ALT, γGT, and FT3 blood concentrations, and insulin resistance (quantified by HOMA-IR) and diastolic and systolic blood pressure levels were significantly lower after VLCKD.
• By contrast, 25 (OH) vitamin D, HDL-cholesterol, and FT4 blood concentrations were higher after VLCKD.
• The variation (δ) of CAP after VLCKD did not correlate with the δ of any other parameter investigated in the study.

To conclude, VLCKD is a helpful approach for NAFLD independence of changes in factors associated commonly with NAFLD (fat mass, obesity, blood pressure, lipids, and insulin resistance) as well as thyroid hormone and vitamin D levels.

Reference:

Rinaldi, Roberta, et al. "The Effects of Eight Weeks' Very Low-Calorie Ketogenic Diet (VLCKD) On Liver Health in Subjects Affected By Overweight and Obesity." Nutrients, vol. 15, no. 4, 2023.