Consumption of Fast Food Linked to Potentially Deadly Liver Disease

Fast Food Burger Fries Drink Combo

A new study from Keck Medicine of USC found that fast food consumption is associated with nonalcoholic fatty liver disease, a serious condition in which fat builds up in the liver. The study revealed that people with obesity or diabetes who consume 20% or more of their daily calories from fast food have severely elevated levels of fat in their liver compared to those who consume less or no fast food. The general population also has moderate increases of liver fat when one-fifth or more of their diet is fast food.

Risk of liver damage is highest for those with obesity or diabetes.

The new year has begun, and with it, resolutions for change.

A study from Keck Medicine of USC published on January 10, 2023, in the journal Clinical Gastroenterology and Hepatology gives people extra motivation to reduce fast-food consumption.

The study found that eating fast food is associated with nonalcoholic fatty liver disease, a potentially life-threatening condition in which fat builds up in the liver.

Researchers discovered that people with obesity or diabetes who consume 20% or more of their daily calories from fast food have severely elevated levels of fat in their liver compared to those who consume less or no fast food. And the general population has moderate increases of liver fat when one-fifth or more of their diet is fast food.

“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.”

Ani Kardashian

Ani Kardashian, MD, a hepatologist with Keck Medicine of USC, is the lead author of a new study showing that fast-food consumption is linked to liver disease. Credit: Ricardo Carrasco III

While previous research has shown a link between fast food and obesity and diabetes, this is one of the first studies to demonstrate the negative impact of fast food on liver health, according to Kardashian.

The findings also reveal that a relatively modest amount of fast food, which is high in carbohydrates and fat, can hurt 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.”

Nonalcoholic fatty liver disease, also known as liver steatosis, can lead to cirrhosis, or scarring of the liver, which can cause liver cancer or failure. Liver steatosis affects over 30% of the U.S. population.

Kardashian and colleagues analyzed the most recent data from the nation’s largest annual nutritional survey, the 2017-2018 National Health and Nutrition Examination Survey, to determine the impact of fast-food consumption on liver steatosis.

The study characterized fast food as meals, including pizza, from either a drive-through restaurant or one without wait staff.

The researchers evaluated the fatty liver measurement of approximately 4,000 adults whose fatty liver measurements were included in the survey and compared these measurements to their fast-food consumption.

Of those surveyed, 52% consumed some fast food. Of these, 29% consumed one-fifth or more daily calories from fast food. Only this 29% of survey subjects experienced a rise in liver fat levels.

The association between liver steatosis and a 20% diet of fast food held steady for both the general population and those with obesity or diabetes even after data was adjusted for multiple other factors such as age, sex, race, ethnicity, alcohol use, and physical activity.

“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.”

She hopes the study will encourage healthcare providers to offer patients more nutrition education, especially to those with obesity or diabetes who are at higher risk of developing a fatty liver from fast food. Currently, the only way to treat liver steatosis is through an improved diet.

Reference: “Quantifying the Negative Impact of Fast-food Consumption on Liver Steatosis Among United States Adults with Diabetes and Obesity” by Ani Kardashian, MD, Jennifer L. Dodge and Norah A. Terrault, 10 January 2023, Clinical Gastroenterology and Hepatology.
DOI: 10.1016/j.cgh.2022.11.040

Jennifer Dodge, MPH, assistant professor of research medicine and population and public health sciences at the Keck School of Medicine of USC and Norah Terrault, MD, MPH, a Keck Medicine gastroenterologist and division chief of gastroenterology and liver diseases at the Keck School, were also authors on the study.

6 Comments on "Consumption of Fast Food Linked to Potentially Deadly Liver Disease"

  1. The definition of a ‘fast food ‘ restaurant in the study was a restaurant with a drive thru or without waitstaff. So according to the article, a burger from a sit-down restaurant is fine, but from Wendy’s, a burger is evil. If you’re studying effects of food, the food should be the defining criteria, not the restaurant it comes from.

    • I agree. The place doesn’t matter. Heck, you can probably find some sit-down restaurants that have way worse nutrition than a fast food place. This article is misleading as it implies going to a full-service restaurant means you have nothing to worry about.

      It’s like claiming an Oreo is vegan. It’s technically true, but eating mostly Oreos on a vegan diet is going to do way more harm than good.

  2. What components of “fast food” are the culprits. There has to be a specific component that is the issue. To state that “fast food” is bad for you with no data to support that statement has no validity. There has to be certain components that are bad. What are they?

    • From the article:

      “The findings also reveal that a relatively modest amount of fast food, which is high in carbohydrates and fat, can hurt the liver.”

      It seems to be the high amount of carbs and fat usually present in fast food. For example, a double cheeseburger at Wendy’s has over 60g of fat in it. That’s your entire recommended daily fat intake in one meal. That’s not even counting the fries.

  3. “A study from Keck Medicine of USC published on January 10, 2013,” I think you mean 2023.

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