From the AGA Journals

Diet packed with fast food found hard on the liver



A new study that quantifies the harm to the liver of eating fast food might motivate people to eat less of it – especially those with obesity or diabetes.

The study finds that getting one-fifth or more of total daily calories from fast food can increase the risk of nonalcoholic fatty liver disease, which can lead to cirrhosis and its complications, including liver failure and liver cancer.

Fast food neon sign on black background. Annbozhko/iStock/Getty Images

Although the magnitude of association was modest among the general population, “striking” elevations in steatosis were evident among persons with obesity and diabetes who consumed fast food, in comparison with their counterparts who did not have obesity and diabetes, the researchers reported.

“My hope is that this study encourages people to seek out more nutritious, healthy food options and provides information that clinicians can use to counsel their patients, particularly those with underlying metabolic risk factors, of the importance of avoiding foods that are high in fat, carbohydrates, and processed sugars,” lead investigator Ani Kardashian, MD, hepatologist with the University of Southern California, Los Angeles, said in an interview.

“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,” Dr. Kardashian added.

The study was published online in Clinical Gastroenterology and Hepatology.

More fast food, greater steatosis

The findings are based on data from 3,954 adults who participated in the National Health and Nutrition Examination Survey (NHANES) of 2017-2018 and who underwent vibration-controlled transient elastography. Of these participants, data regarding 1- or 2-day dietary recall were available.

Steatosis, the primary outcome, was measured via controlled attenuation parameter (CAP). Two validated cutoffs were utilized (CAP ≥ 263 dB/m and CAP ≥ 285 dB/m).

Of those surveyed, 52% consumed any fast food, and 29% derived 20% or more of their daily calories from fast food.

Fast-food intake of 20% or more of daily calories was significantly associated with greater steatosis after multivariable adjustment, both as a continuous measure (4.6 dB/m higher CAP score) and with respect to the CAP ≥ 263 dB/m cutoff (odds ratio [OR], 1.45).

“The negative effects are particularly severe in people who already have diabetes and obesity,” Dr. Kardashian told this news organization.

For example, with diabetes and fast-food intake of 20% or more of daily calories, the ORs of meeting the CAP ≥ 263 dB/m cutoff and the CAP ≥ 285 dB/m cutoff were 2.3 and 2.48, respectively.

The researchers said their findings are particularly “alarming,” given the overall increase in fast-food consumption over the past 50 years in the United States, regardless of socioeconomic status.

Diet coaching

The finding that fast food has more deleterious impact on those with obesity and diabetes “emphasizes that it is not just one insult but multiple factors that contribute to overall health,” said Nancy Reau, MD, section chief of hepatology at Rush University Medical Center in Chicago.

“This is actually great news, because diet is modifiable, vs. your genetics, which you currently can’t change. This doesn’t mean if you’re lean you can eat whatever you want, but if you are overweight, being careful with your diet does have impact, even if it doesn’t lead to substantial weight changes,” said Dr. Reau, who is not affiliated with the study.

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,” Dr. Reau said in an interview.

Fast food and fatty liver go “hand in hand,” Lisa Ganjhu, DO, gastroenterologist and hepatologist at NYU Langone Health in New York, told this news organization.

“I counsel and coach my patients on healthy diet and exercise, and I’ve been pretty successful,” said Dr. Ganjhu, who was not involved with the study.

“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 carbohydrates, they are more apt to continue,” Dr. Ganjhu said.

The study was funded by the University of Southern California. Dr. Kardashian, Dr. Reau, and Dr. Ganjhu have disclosed no relevant financial relationships.

A version of this article first appeared on

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