Jan. 13, 2023 – A new study that shows the harm to the liver of eating fast food might provide people with motivation to eat less of it in the new year.
The study found that eating at least 20% of total daily calories from fast food can increase the risk of nonalcoholic fatty liver disease, a potentially life-threatening condition where fat builds up in the liver. The disease can lead to cirrhosis and its complications, including liver failure and liver cancer.
People with obesity or diabetes are more vulnerable to the harmful effects of fast food on the liver, although the general population is not immune to the harm.
“My hope is that this study encourages people to seek out more nutritious, healthy food options,” says lead investigator Ani Kardashian, MD, with Keck Medicine at the University of Southern California.
“At a policy level, public health efforts are needed to improve access to affordable, healthy, and nutritious food options across the U.S. This is especially important as more people have turned to fast foods during the pandemic and as the price of food as risen dramatically over the past year due to food inflation,” she says.
The researchers analyzed data on diet and fatty liver measurements for nearly 4,000 adults.
Nearly 30% of them got 20% or more of their total daily calories from fast food, such as burgers, fries, pizza, and the like.
They found that people with obesity or diabetes who take in one-fifth or more of their daily calories from fast food had severely high levels of fat in their liver, compared with those who eat less or no fast food.
The general population had moderate increases in liver fat when one-fifth or more of their diet was made up of fast food.
The findings are particularly “alarming” given the increase in fast-food consumption over the past 50 years, regardless of socioeconomic status, Kardashian says.
“If people eat one meal a day at a fast-food restaurant, they may think they aren’t doing harm. However, if that one meal equals at least one-fifth of their daily calories, they are putting their livers at risk,” she says.
For people who have limited options and need to eat fast food, “there are healthy choices at most restaurants; you just need to be smart about reading labels, watching calories, and ordering the healthier options,” says Nancy Reau, MD, with Rush University Medical Center in Chicago, who wasn’t involved in the study.
Lisa Ganjhu, DO, with NYU Langone Health in New York City, agrees.
“I am a firm believer that fast food can cause fatty liver. It goes hand in hand, and I counsel and coach my patients on healthy diet and exercise, and I’ve been pretty successful,” she says.
“If my patient is eating at McDonald’s a lot, I basically walk through the menu with them and help them find something healthy. When patients see the benefits of cutting out fat and reducing carbohydrate, they are more apt to continue,.”