Donald Trump has a serious weight problem: He can’t seem to stop criticizing the girth of others.

For decades, Trump has commented on other people’s bodies, particularly women who he believes had gained too much weight or were, in his word, “fat.” The recurring habit flared again this week when the Republican presidential nominee attacked the size of a Miss Universe winner, claiming she had gained “a massive amount of weight” while she wore the pageant’s crown and that “it was a real problem.”

Trump called actress Rosie O’Donnell a “fat pig” and said she has a “fat, ugly face.” He said singer Jennifer Lopez has a “fat a--” and said reality television star Kim Kardashian had “gotten a little large” during her pregnancy. He kept a “fat photo” of one employee whose weight fluctuated in a drawer and told an overweight executive, “you like your candy,” according to the employees. When a reporter complimented his wife, Melania, on her appearance shortly after giving birth, Donald Trump replied: “She’s lost almost all the baby weight.”

Trump also mocks the weight of men, but usually in a more jocular way than his remarks about women. Trump reportedly told a producer on “The Apprentice” that “everybody loves a fat guy,” and he has joked about New Jersey Gov. Chris Christie’s size on the campaign trail.

Trump’s comments about weight, along with a long line of other incendiary comments about women, present another serious challenge for him in attracting female voters in November. Trump needs to gain support from moderate suburban women to ascend to the White House, but so far he has found little success with female voters, many of whom find the Republican nominee offensive and unacceptable. According to an ABC News-Washington Post poll released this week, 55 percent of women surveyed said they plan to vote for Democratic nominee Hillary Clinton.

At the Sept. 26 presidential debate, Hillary Clinton knocked Donald Trump for his treatment of former Miss Universe Alicia Machado. Here's what you need to know about Machado. (Monica Akhtar/The Washington Post)

Trump’s obsession with weight carries some irony for a candidate who boasts about his unhealthy eating habits, dining regularly on McDonald’s hamburgers and buckets of KFC fried chicken on his private jet. By his own public accounting of his medical health, Trump is just five pounds shy of being considered obese under the body mass index.

“I work out on occasion . . . as little as possible,” Trump said at a 1997 news conference during which he mocked the weight of reporters.

Trump has long commented on women he believes are attractive, including his daughter, Ivanka, whom Trump said has a “very nice figure.” But he also has singled out celebrities for verbal abuse about their weight, including O’Donnell and Kardashian. He said Kardashian has a “bad body” and that she shouldn’t dress “like you weigh 120 pounds,” a comment he made while she was pregnant.

Tim Miller, a longtime Republican strategist and a staunch Trump opponent who worked for Jeb Bush during the GOP primary campaign, said Trump’s insults about weight and other physical characteristics and his general lack of discipline raise serious questions about his temperament.

“He’s a middle schooler who is filled with insecurities and insults people to try to deal with his insecurities,” Miller said.

Ana Navarro, a Republican strategist, tweeted: “I’ve struggled w/weight issues all my life. And I agree. A man who shames and bullies a woman for her weight, isn’t even fit to be a man.”

This archive video from 1997 shows Republican presidential nominee Donald Trump with his now outspoken critic, former Miss Universe Alicia Machado. (Reuters)

Trump’s campaign did not respond to requests for comment Wednesday about his history of remarks about people’s weight.

The latest controversy erupted at the tail end of Monday night’s first presidential debate, when Clinton brought up Alicia Machado, who was crowned Miss Universe in 1996 at a time when Trump was a partner in the group that owned the pageant. During her reign, Machado was caught up in a tabloid- and Trump-fueled uproar over her weight.

In 1997, Trump publicly claimed the Venezuelan pageant queen had gained up to 60 pounds, but she said it was no more than 19. Machado says she gained the weight when she returned to eating normally after suffering from anorexia and bulimia before the competition. Trump went so far as to ambush Machado in a New York gym, where he held a news conference criticizing her weight as she sat on a stationary bike and jumped rope in front of dozens of television cameras.

“We’ve tried diet, spa, a trainer, incentives. Forget it, the way she’s going, she’d eat the whole gymnasium,” Trump told Newsweek at the time.

Machado, now a U.S. citizen, says Trump called her “Miss Piggy” in reference to her weight and “Miss Housekeeping” in reference to her ethnicity — both of which were highlighted by Clinton on the debate stage Monday.

In a conference call arranged by Clinton’s campaign Tuesday, Machado said Trump “always treated me like a lesser thing, like garbage.”

Trump has reacted angrily, telling Fox News on Tuesday: “She was the worst we ever had, the worst, the absolute worst, she was impossible. She gained a massive amount of weight, and it was a real problem. We had a real problem. Not only that, her attitude.”

Trump surrogate Kayleigh McEnany said on CNN that Trump didn’t force Machado to work out, and she defended the candidate for calling Machado an “eating machine” in 1997.

“I like to eat. I like to eat. That is not necessarily a sexist thing,” McEnany said.

Some Trump allies also highlighted news reports about a 1988 incident in Venezuela in an attempt to undercut Machado’s credibility. The reports said Machado was suspected of driving the getaway car after her then-boyfriend allegedly shot a man and then threatened the judge in the case; no charges were ever filed against her. Machado brushed off the case on CNN on Tuesday, calling the reports “speculation.”

Trump sought to put the controversy to rest Wednesday, stating during an interview several times that in fact he had “saved her job.”

“I saved her job because they wanted to fire her for putting on so much weight,” Trump told Bill O’Reilly on Fox News on Wednesday. “And it is a beauty contest, you know. I mean, say what you want, they know what they’re getting into. It’s a beauty contest. And I said don’t do that.

“And you know what happened? Look what I get out of it. I get nothing,” Trump added later.

Trump’s latest comments about Machado’s weight were widely pilloried, with Democrats and some Republicans saying the sharp-tongued businessman had again gone too far.

In a radio interview Wednesday, President Obama said Trump insults women “in terms of how he talks about them and talks about their weight and talks about how they look instead of the content of their character and their capabilities.”

Katie Packer, a GOP strategist who opposes Trump, said: “He only seems to place value based on physical appearance. To so publicly humiliate and denigrate a woman who was at least beautiful enough to become Miss Universe sends a signal that he has pretty specific standards for what he considers to be ideal.”

Sen. Claire McCaskill (D-Mo.), a prominent Clinton surrogate, responded Wednesday with a sarcastic tweet referencing Trump’s size.

“The D women Senators have talked & we’re concerned about Donald’s weight,” she tweeted. “Campaign stress? We think a public daily weigh-in is called for.”

In a letter released this month from his personal doctor, Trump, 70, was listed as being 6 feet, 3 inches tall and weighing 236 pounds, making him overweight and on the verge of being obese for that height. The note said he was overall “in excellent physical health.”

At a rally this week in Melbourne, Fla., some women who support Trump were not bothered by his comments on Machado.

“I think it’s nonsense. It’s a business. He ran beauty pageants — so what?” said Ellen Kaufman, 56. “I think we all like a thing of beauty, we all like to look at pretty people. . . . Bill Clinton certainly liked to look at pretty people.”

But Andrea Franz, 54, of Boston, who attended a Clinton rally in Durham, N.H., Wednesday, said Trump’s remarks are emblematic of his general views on women.

“The fact that does he honestly believe at some level, that he is a superior person and that the women he’s talking to are not — that they’re fat, or they’re whatever. . . . It just showed his colors,” she said.

Jenna Johnson in Melbourne, Fla., and Anne Gearan in Durham, N.H., contributed to this report.