It afflicts an estimated 20 to 30% of people in Western countries, yet most people have never heard about nonalcoholic fatty liver disease (NAFLD), nor have they heard about nonalcoholic steatohepatitis (NASH), an advanced form of NAFLD, which afflicts around 17% of the population.1,2,3
Pharmaceutical companies, however, are rushing to develop drugs for these lifestyle-related diseases. Within the next 5 years, the market for such drugs is expected to swell to $8 billion.4
What are these diseases and why are they so unknown? In this article, we’ll answer those questions, while also examining why the Paleo diet can play a big role in treatment.
What Causes Liver Fat Accumulation?
NAFLD is characterized by the accumulation of liver fat (triglycerides) by people consuming less than 20 grams of alcohol per day.5 This accumulation, which develops slowly and subtly over the course of many years, can progress into NASH and even cirrhosis. NASH is the advanced form of NAFLD, which features inflammation and fibrosis (scar tissue) within the liver, plus increased fat accumulation.
The precise etiology (the manner of causation) of NAFLD is unknown, but the disease is strongly associated with obesity, insulin resistance, diabetes, and hyperlipidemia (excessive levels of fat within the blood). For example, about 80 to 90% of obese adults have NAFLD, as do 30 to 50% of diabetes patients, and upwards of 90% of hyperlipidemia patients.6 Furthermore, as reported by Tolman et al., “what is common to virtually all patients with NAFLD is insulin resistance.”7
Preventing NAFLD and NASH therefore starts by preventing insulin resistance, which in turn starts by adopting a healthy diet and lifestyle practices. By eliminating cereals, sugar, and other rapidly digestible carbohydrates, for example, the Paleo diet helps normalize insulin levels. Those types of carbohydrates are what Dr. David Ludwig refers to as “the ultimate fat cell fertilizer.” They produce the most insulin, thereby triggering fat accumulation.8
Put another way, it’s not dietary fat that makes you fat; excessive carbohydrate consumption, particularly sugar, is the far more likely culprit. The same holds true for liver fat accumulation. Perhaps to an even greater extent. For example, Sevastianova et al. administered high-carb diets to overweight adults for 3 weeks, resulting in “a >10-fold greater relative change in liver fat (27%) than in body weight (2%).”9
Compared to glucose, excessive fructose consumption is particularly detrimental for liver health because the liver bears most of the burden of fructose metabolism.10 In a recent review published in Hepatobiliary Surgery and Nutrition, Basaranoglu et al. characterized fructose as a “weapon of mass destruction” with respect to NAFLD. The authors wrote, “ingested carbohydrates are a major stimulus for hepatic de novo lipogenesis (DNL) and are more likely to directly contribute to NAFLD than dietary fat.”11 They went on to demonstrate that high fructose corn syrup (HFCS) consumption, particularly HFCS-containing beverages, is associated with NAFLD based on the lipogenic and proinflammatory effects of fructose.
