Lost what? The Iowa Caucus? Iowa hasn't predicted the eventual Republican nominee in ages. As a matter of fact, it's nearly become the kiss of death to win it.
McCain took 4th place in the 2008 Iowa Caucus. Same as Newt just did. The real primary begins in South Carolina. If Newt loses that, or if Santorum beats all the odds and wins it, then we'll talk about Gingrich "losing".
2000 Iowa Republican caucus
George W. Bush (41%)
Steve Forbes (31%)
Alan Keyes (14%)
Gary Bauer (9%)
John McCain (5%)
Orrin Hatch (1%)
I guess if we define "ages" as "the most recent Republican to win the white house", your statement would be correct. Bush won the 2000 and 2004 Iowa caucus. And of course, the most recent Democrat to win the White House (who is in power right now), started his presidential campaign with a upset victory over Hillary Clinton in the Iowa caucus.
I would agree if Gingrich fans said "the Iowa caucus winner doesn't necessarily win the nomination", but instead they're claiming that Iowa "only produces flukes" and "no Iowa winner has won the nomination in ages" when it reality about 2/3rds of the Presidential nominees started with a victory in Iowa, including the 2 most recent presidents (Obama & George W. Bush).