Alexa Crisostomo of Eagle Rock said she goes through fast food drive-thrus maybe three times a week.

"If you're going, even every couple of days, that's probably still too much," said lead study author and hepatologist Dr. Ani Kardashian with Keck Medicine of USC.

If convenience-style foods make up 20% of your diet, Kardashian's findings reveal how that elevates your risk for a fatty liver.

Researchers analyzed data from a national survey - 29% said a fifth of their calories came from fast food, and that same 29% were the ones who experienced higher liver fat.

Kardashian said packing lean proteins, whole grains, fruits and veggies from home can be more convenient than a drive-thru.

About 30% of people in the United States have non-alcoholic, fatty, liver disease - and many don't know they have it.