Fast Food Linked To Liver Disease

Nonalcoholic fatty liver disease, also known as liver steatosis is a potentially life-threatening condition where fat builds up in the liver, this can lead to cirrhosis, or scarring of the liver which can cause liver cancer or liver failure. Estimates are that over 30% of America is affected by liver steatosis. 

According to the researchers, those with diabetes or obesity who consume 20% or more of their daily calories from fast foods have severely elevated levels of fat in their livers when compared to those who don’t eat fast food or those who consume less. Findings also show that even modest amounts of fast foods high in fat and carbohydrates can harm the liver. Additionally, the general population has moderate increases in liver fat when one-fifth or more of their diet is composed of fast foods. 

"Healthy livers contain a small amount of fat, usually less than 5%, and even a moderate increase in fat can lead to nonalcoholic fatty liver disease," said Ani Kardashian, MD, a hepatologist with Keck Medicine and lead author of the study. "The severe rise in liver fat in those with obesity or diabetes is especially striking, and probably due to the fact that these conditions cause a greater susceptibility for fat to build up in the liver."

"If people eat one meal a day at a fast-food restaurant, they may think they aren't doing harm," said Kardashian. "However, if that one meal equals at least one-fifth of their daily calories, they are putting their livers at risk."

For this study data was analyzed from the 2017-2918 National Health and Nutrition Examination Survey to determine the impact of fast food consumption on liver steatosis. Fatty liver measurements were evaluated from approximately 4,000 adults whose measurements were included in the survey and compared those to their fast food intake. Fast food was characterized as meals including drive-through restaurants, pizza, take-out, or a restaurant without wait staff. 

52% of the participants were found to have consumed some fast food, of those 29% consumed at least one-fifth or more of their daily calories from fast foods, and only this 29% experienced an increase in liver fat levels. According to the researchers, the association between liver steatosis and a 20% diet of fast foods remained steady for the general population and those with diabetes or obesity even after adjusting for factors such as physical activity, alcohol use, ethnicity, race, age, and gender. 

"Our findings are particularly alarming as fast-food consumption has gone up in the last 50 years, regardless of socioeconomic status," said Kardashian. "We've also seen a substantial surge in fast-food dining during the COVID-19 pandemic, which is probably related to the decline in full-service restaurant dining and rising rates of food insecurity. We worry that the number of those with fatty livers has gone up even more since the time of the survey."

Other studies have demonstrated a link between diabetes and obesity and fast food, this is one of few that demonstrates the negative impact of fast foods on liver health, according to the researchers who hope their findings encourage healthcare providers to offer more nutrition education to patients, especially those with diabetes or obesity who are at an increased risk of developing fatty liver from poor dietary choices. At the moment the only way to treat liver steatosis is through an improved diet.