University of Michigan economics professor Justin Wolfers has trashed Donald Trump’s claim that grocery prices are down.

The president told Fox News’ Laura Ingraham in an interview that aired this week that the United States is “doing phenomenally well” under his leadership and currently enjoys the “greatest economy we’ve ever had,” with just beef and coffee prices too high.

“Look, every word the president just said is a lie,” Wolfers told CNN’s Kaitlan Collins on Tuesday. “Worse with that, it’s such a lie that I worry that there’s literally a break with reality inside the man’s mind. I can tell you that because I’m a statistics nerd, and you can go to the Bureau of Labor Statistics, they’ve got people in supermarkets all across the country and almost every category of goods or services sees the prices rising.”

Wolfers acknowledged there’s a “reasonable argument to be had” about whether inflation is too high or too low.

But the fact remains that there is most definitely inflation, he said.