Mediterranean low-carb diet has the edge for reducing liver fat
Excessive storage of fat in the liver is strongly associated with insulin resistance, metabolic syndrome, and increased cardiovascular disease risk.
If you have fatty liver disease or metabolic syndrome, you may be interested in a new study suggesting that following a low-carb diet reduces liver fat more effectively than a low-fat diet.
In this study, 278 people with either abdominal obesity or low HDL cholesterol and high triglycerides (three of the five criteria for metabolic syndrome) were randomly assigned to follow a low-fat diet or Mediterranean low-carb diet for 18 months. Importantly, most of these individuals had excessive fat stored in their liver; on average, their liver fat content was 10%. (Although a small amount of fat it in the liver is normal, anything above 5% is considered too high.) Additionally, slightly over half of the study participants had nonalcoholic fatty liver disease (NAFLD).
Both groups were encouraged to consume whole foods, increase vegetable intake, and avoid trans fats and refined carbohydrates. The low-fat diet group consumed generous amounts of whole grains, fruits, and legumes, and restricted fat to less than 30% per day; by contrast, the Mediterranean low-carb group consumed more fat and protein (especially fish and poultry), ate fewer than 40 grams of carbs for the first two months, and gradually increased their intake to 70 grams of carbs per day in the form of vegetables, nuts, seeds and legumes. The low-carb group also included 28 grams of walnuts in their diet every day from the third month on.
By the end of the study, all of the participants had lost weight from their liver and around their midsection. However, the low-carb group experienced a significantly greater reduction in liver fat (as measured by MRI) than the low-fat group, regardless of their overall change in abdominal cavity fat. Moreover, this occurred in people with NAFLD as well as those without fatty liver disease. In addition, improvements in liver function markers were more pronounced in the low-carb group, along with many of the usual outcomes of carb restriction (lower triglycerides, higher HDL cholesterol levels, and lower diastolic blood pressure).
What does this study tell us? First, reducing intake of processed carbs and industrial seed oils and trans fats, consuming more whole foods, and avoiding overeating leads to loss of liver and abdominal fat regardless of macronutrient composition. However, a Mediterranean, low-carb diet appears to have the edge over a low-fat diet when it comes to decreasing liver fat and improving fatty liver disease. Given the many benefits of carb-restricted diets on appetite, blood sugar, and insulin resistance, following this way of eating may be your best bet for protecting liver health and reducing cardiometabolic risk.