LONDON – A low-carbohydrate, high-fat (LCHF) diet reduced the progression of nonalcoholic fatty liver disease (NAFLD), and despite no calorie restriction, participants with both NAFLD and type 2 diabetes lost 5.8% of their body weight, according to a randomized controlled study.
“Based on these results, the LCHF diet may be recommended to people with NAFLD and type 2 diabetes,” said Camilla Dalby Hansen, MD, department of gastroenterology and hepatology, Odense University Hospital, Denmark, who presented the data at the International Liver Congress (ILC) 2022.
“Basically, if you have fat in your liver, you will benefit from eating fat,” she said.
The LCHF diet was compared with a low-fat, high-carbohydrate diet more typically followed for these conditions. The low-fat diet was also found to reduce the progression of NAFLD, but to a lesser extent than the LCHF diet.
Dr. Dalby Hansen called their study one of the most extensive investigations of the LCHF diet in patients with type 2 diabetes and fatty liver disease.
“Combining this [reduction in NAFLD score] with the huge weight loss, the lower HbA1c [blood sugar], the lowering of blood pressure in women, the rise in HDL levels, and reduction in triglycerides – all in all, this diet is very promising,” she said.
Stephen Harrison, MD, visiting professor, University of Oxford, United Kingdom, medical director of Pinnacle Clinical Research and president of Summit Clinical Research, San Antonio, commended Dr. Dalby Hansen on her methodology, which included before-and-after liver biopsies. “It’s a heinous effort to do paired liver biopsies in a lifestyle modification trial. That’s huge.”
“This study tells me that the way we manage patients doesn’t change – it is still lifestyle modification,” said Dr. Harrison, who was not involved with the study. “It’s eat less [rather] than more. It’s exercise and try to lose weight. In the long term, we give patients benefit, and we show that the disease has improved, and we offer something that means they can maintain a healthy life.”
He added that the relatively small and short trial was informative.
“They improved the NAFLD activity score [NAS],” he said. “I don’t know by how much. There was no change in fibrosis, but we wouldn’t expect this at 6 months.”
“It’s provocative work, and it gives us healthy information about how we can help manage our patients from a lifestyle perspective,” he concluded.
‘Do not lose weight. Eat until you are full’
In the study, 110 participants with type 2 diabetes and NAFLD, aged 18-78 years, were allocated to the LCHF diet, and 55 were allocated to the low-fat diet for 6 months.
The researchers performed liver biopsies at baseline and 6 months, which were blinded for scoring.
Participants had ongoing dietitian consultations, with follow-up visits at 3 and 6 months. Compliance was reported continuously through an online food diary platform.
The primary endpoint was change in glycemic control as measured by A1c level over 6 months. The secondary endpoints comprised the proportion of participants with changes in the NAS of at least 2 points over 6 months. Both these measures were compared between the two dietary groups.
The two groups were matched at baseline, with a mean age of 55-57 years, 58% were women, 89% with metabolic syndrome, and a mean BMI 34 kg/m2.
In baseline liver disease, F1 level fibrosis was the most common (58%), followed by hepatic steatosis (S1, 47%; S2, 32%), with a median NAS of 3, and 19% had nonalcoholic steatohepatitis.
The special thing about these diets was that participants were told to “not lose weight, but eat until you are full,” remarked Dr. Dalby Hansen.
Those on the LCHF diet consumed an average of 61% energy from fat, 13% from carbohydrates, and 23% from protein, compared with the low-fat diet, which comprised an average of 29% energy from fat, 46% from carbohydrates, and 21% from protein.
“It’s a lot of fat and corresponds to a quarter of a liter of olive oil per day,” said Dr. Dalby Hansen. “They really had to change their mindset a lot, because it was difficult for them to start eating all these fats, especially since we’ve all been told for decades that it isn’t good. But we supported them, and they got into it.”
The LCHF diet was primarily comprised of unsaturated fats – for example, avocado, oil, nuts, and seeds – but also included saturated fats, such as cheese, cream, and high-fat dairy products. Participants were free to eat unsaturated and saturated fats, but Dr. Dalby Hansen and her team advised participants that “good” unsaturated fats were preferable.
“Also, this diet contained vegetables but no bread, no potatoes, no rice, and no pasta. It was low in carbohydrates, below 20%,” she added.