Within the past few years, Jamie Oliver has faced some of the biggest challenges of his career.

Since his first appearance on The Naked Chef in 1999, the celebrity chef had gone on to achieve success through numerous hit television shows, cookbooks, charities and health campaigns. However, the 43-year-old is now dealing with a troubled business empire and a series of controversies that has reportedly turned fans away.

Public relations expert Catriona Pollard said Oliver’s downfall was caused by blunders such as overexposure, actions that do not match his personal brand, and failure to address public criticisms.

Oliver’s image as a healthy everyday cook does not hold up with his actions, Pollard told news.com.au.

Oliver was well-known for his easy, budget-friendly recipes, as shown in the television show Jamie’s Money Saving Meals. However, his eateries are priced on a premium. For example, the Australian branches of Jamie’s Italian restaurant chain ask $20 for a one-course lunch.

Last year, Oliver said the chain had “run out of cash” and closed 12 of the restaurants in Britain.

“You can buy one of his books for $20, or watch his TV show for free,” said Pollard. “But a lot of his restaurants sold expensive meals … which didn’t really stack up for people.”

Pollard said linking his name to the restaurants was a mistake, as their failures would be connected to his personal reputation.

Oliver is also a proud advocate of healthy foods and sustainability as the UN Environment’s environmental champion. The public was quick to accuse Oliver of hypocrisy after the chef signed a £5 million (AU$9 million) deal with petrol giant Shell, which is one of the top 10 greenhouse gas-producing companies in the world.

“Jamie Oliver has a very distinct personal brand linked to very distinctive values,” said Pollard.

“He’s so outspoken when it comes to things like healthy eating and the environmental impacts of climate change, which is great, but … the deal with Shell was seen as negatively straying from that very distinct brand.

“It gave people fodder and they started to change their opinions of him. That backlash was caused because people thought he wasn’t behaving the way they thought he should.”

On Monday, the chef was also revealed to have been an informal advisor to McDonald’s for years, despite having dubbed their burgers as “not fit for human consumption” in 2011.

Pollard also noted Oliver’s media gaffes as one of the reasons the public is turning away from the Brit. While Oliver said nothing on the Shell deal, he revealed the royal family’s rejection to his offer to cater for Prince Harry’s wedding.

“He absolutely should have kept quiet at a time when people were already questioning his reputation — it was not a very sensible thing to do, to say he was snubbed by one of the most watched marriages in recent history,” she said.

“It made people think [the royals] didn’t want to be associated with him, which was a misstep.”

Pollard said it is not too late for Oliver to address these problems. “He’s absolutely not down and out — but he needs to think twice before saying something in future … and look back at what made him great in the first place, and make sure he stays aligned to those values people were attracted to.”