Keck Medicine at USC released a research in Clinical Gastroenterology and Hepatology that gives extra reason for consumers to limit their fast-food intake. The study discovered that consuming fast food is linked to nonalcoholic fatty liver disease, a potentially fatal illness in which fat accumulates in the liver. Researchers observed that patients with obesity or diabetes who eat fast food for 20% or more of their daily calories had much higher amounts of fat in their liver than those who eat less or no fast food. When one-fifth or more of their diet consists of fast food, the general population has moderate increases in liver fat.
“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, adding, “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.”
While prior study has revealed a correlation between fast food and obesity and diabetes, Kardashian claims that this is one of the first studies to indicate the deleterious impact of fast food on liver health.
The findings also show that even a small amount of fast food, which is heavy in carbs and fat, might harm the liver.
“If people eat one meal a day at a fast-food restaurant, they may think they aren’t doing harm,” said Kardashian, adding, “However, if that one meal equals at least one-fifth of their daily calories, they are putting their livers at risk.”
Nonalcoholic fatty liver disease, commonly known as liver steatosis, can progress to cirrhosis, or scarring of the liver, which can lead to liver cancer or failure. Over 30% of the population in the United States suffers from liver steatosis.
Kardashian and colleagues used the most recent data from the nation’s biggest annual nutritional survey, the 2017-2018 National Health and Nutrition Examination Survey, to establish the influence of fast-food intake on liver steatosis.
The study defined fast food as meals, including pizza, from a drive-through or a restaurant with no wait staff.
The researchers compared the fatty liver measures of almost 4,000 persons whose fatty liver values were included in the study to their fast-food intake. 52% of those polled had eaten fast food. 29% of these people got one-fifth or more of their daily calories from fast food. Only 29% of study participants reported an increase in liver fat levels.
Even when data was controlled for age, gender, race, ethnicity, alcohol consumption, and physical activity, the link between liver steatosis and a 20% fast food diet remained consistent in both the general population and those with obesity or diabetes.
“Our findings are particularly alarming as fast-food consumption has gone up in the last 50 years, regardless of socioeconomic status,” said Kardashian, adding, “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.”
She expressed optimism that the findings will motivate health care practitioners to deliver more nutrition education to patients, particularly those with obesity or diabetes who are at a higher risk of getting a fatty liver from fast food. At the moment, the only option to treat hepatic steatosis is to change one’s diet.