Exercise and a hypocaloric, Mediterranean-style diet remain first-line interventions that can benefit all patients with nonalcoholic fatty liver disease (NAFLD), according to a clinical practice update from the American Gastroenterological Association.
“[W]eight loss is associated with a reduction in liver fat, which provides a potential for reversal of disease progression,” wrote Zobair M. Younossi, MD, MPH, of Inova Fairfax Medical Campus in Falls Church, Va., with his associates. Lifestyle modifications remain “the cornerstone for management” because, even though NAFLD affects approximately 25% of individuals worldwide according to one meta-analytic assessment, interventions such as medications, bariatric endoscopy, and surgery are usually reserved for the subset of patients with severe obesity, comorbid diabetes, or nonalcoholic steatohepatitis (NASH) with at least stage 2 fibrosis, the experts wrote in Gastroenterology.
They note that clinically significant weight loss typically requires a hypocaloric diet of 1,200-1,500 kilocalories/day or a decrease of 500-1,000 kilocalories/day from baseline. A Mediterranean diet of fresh vegetables, fruits, legumes, minimally processed whole grains, fish, olive oil, nuts, and seeds is recommended because its antioxidant, anti-inflammatory effects may slow NAFLD progression. This diet minimizes or eliminates sweets, refined grains, and red and processed meats. Fructose from fruit is not associated with NAFLD, but patients should consume little or no commercially prepared fructose, which has been linked to visceral adiposity, insulin resistance, hepatic inflammation, and fibrosis progression. Other hypocaloric diets have not been studied enough to support their routine use in NAFLD treatment, according to the clinical practice update.
For patients with NASH, which is the more severe form of NAFLD and is associated with significant morbidity and mortality caused by complications from cirrhosis, hepatic decompensation, and hepatocellular carcinoma, weight loss also has a big impact: Losing at least 5% of total body weight can decrease hepatic steatosis, losing at least 7% can resolve NASH, and losing at least 10% can lessen or stabilize hepatic fibrosis, according to level 1 evidence cited by the update. Weight loss “can significantly impact all aspects of NAFLD histology including fibrosis, but a goal of 10% total body weight loss should be considered for patients with overweight or obese NAFLD,” the authors wrote. Fat loss also improves liver histology in patients with lean NAFLD (body mass index, 26 kg/m2 in non-Asian patients or 24 in Asians), for whom a hypocaloric diet targeting a more modest 3%-5% total body weight loss is recommended.
Because aerobic exercise reduces hepatic fat levels independently of hypocaloric diet, patients with NAFLD should consider a weekly regimen of 150-300 minutes of moderate-intensity exercise or 75-150 minutes of vigorous activity. Resistance training can complement aerobic exercise “but [is] not a replacement,” the authors noted. In addition, patients with NAFLD should restrict alcohol consumption to reduce the risk for liver-related events, and those with advanced hepatic fibrosis should “avoid alcohol entirely.” These recommendations reflect the findings of a large prospective study in which the consumption of even low amounts of alcohol led to worse liver-related outcomes among patients with NAFLD.
Clinicians should screen for and “aggressively” manage common NAFLD comorbidities, including diabetes mellitus, hypertension, and obstructive sleep apnea, according to the clinical practice update. Patients with coexisting metabolic conditions should be risk-stratified for cardiovascular disease and treated based on guidelines from the American College of Cardiology and the American Heart Association.
It is believed that sarcopenia affects patients with NASH cirrhosis because their livers cannot effectively store, metabolize, or mobilize carbohydrates, which leads to a catabolic state in which protein and fat are used as energy sources, according to the update. To avoid exacerbations, these patients may need to optimize their protein intake – a minimum of 1.2-1.5 g/kg of body weight is recommended – from sources of branched-chain amino acids, such as chicken, fish, eggs, nuts, lentils, or soy. Patients with sarcopenic NAFLD also should consume small, frequent meals spaced no more than 4-6 hours apart. When possible, they should consult with a specialized nutritionist. Moderate-intensity exercise may also benefit patients experiencing sarcopenia.
The researchers disclosed ties to Gilead Sciences, Intercept, Bristol Myers Squibb, Novo Nordisk, and several other companies. The review was commissioned and approved by the AGA Institute’s Clinical Practice Updates Committee and the AGA Governing Board.
SOURCE: Younossi ZM et al. Gastroenterology. 2020 Dec 8. doi: 10.1053/j.gastro.2020.11.051.
This article was updated Feb. 10, 2021.