There's one ingredient the Royal Family refuses to eat.

Image: Getty.

Even if you’re the staunchest republican in the country, you can’t help but be a little bit curious about the private life of the Royal Family.

What do these fancy people do all day? Do they ever get bored? What are their dinner table conversations like? And, more importantly — what do they actually eat?

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Well, we finally have an answer to one of those questions. English chef Carolyn Robb has just written The Royal Touch, a book about her experience as Kensington Palace’s full-time cook.

Between 1989 and 2000, Robb fed Prince Charles, the late Princess Diana, and their two sons, Princes William and Harry wherever they happened to live and travel at the time.

In an interview with Racked, Robb has served up a few tasty morsels of behind-the-scenes intel. Here are some of the most intriguing tidbits...

Garlic is banned

Royals do not have time for garlic-laced breath, it seems. Imagine a life without garlic bread, garlic prawns... would that even be worth living?

"The only thing that was forbidden was garlic. And the reason for that was that they obviously did a lot of public engagements and were in close proximity to people and never wanted to have garlic," Robb says. Perhaps we should send the Royal Family a link to our article about the best foods to combat garlic breath? (Post continues after gallery.)

They're not super 'fancy'

Were you expecting the Royal menu to be exclusively caviar and gold leaf-based? Somewhat surprisingly, their diet was fairly un-extravagant and not particularly costly, with a lot of fruit and veg produce coming from Charles and Diana's Highgrove garden.

"When they were home, they preferred really simple, fresh, homemade meals... Lamb would come from the estate, milk would come from the cows on the estates. The pheasants and game were shot so that was no cost and the wild mushrooms, we’d pick and use them throughout the year," Robb explains.

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"It was quite economical, the way the kitchen was run. We would do more extravagant things if we were entertaining."

Robb says while Charles and Diana sometimes received truffles and caviar as gifts, they would never actually buy them. As for the Queen, she favoured a "fairly simple, traditional English diet".

They favour home-made

"Everything was from scratch: bread, pasta, ice cream, as well as ingredients like mayonnaise. As a chef, it’s a real privilege where you’re in a job where you’re able to do that type of stuff!" Robb says.

The boys weren't picky

"They were amazingly good. Princess Diana was the one who decided what they were going to eat. Like all children, they had their things they liked to eat, but they’d eat roast chicken, Shepard’s pie, homemade fish fingers. And quite early on, they started eating game," Robb says. Lucky Charles and Diana, hey?

RELATED: 5 ways to get healthy food into your kids’ mouths (rather than on the floor).

Will and Harry also enjoyed baking cookies and meringue with the chefs as boys, and as they grew older they asked Robb to teach them how to make spaghetti bolognese and other dinner recipes.

Kate does her own cooking

Although Robb's tenure with the Royal Family has been long finished, she still has some insight into how their catering operates today. And guess what? Will and Kate (and their two bubs) don't have a personal chef, and Kate is currently doing the bulk of the family's cooking (although maybe with some help from aspiring nutritionist Pippa).

"You have to remember that she’s not royal. She comes from a normal background and a normal home where she’s always cooked for herself. And what I’ve always heard is that William enjoys spending time with her family because they just eat together at the kitchen table like a normal family," Robb says.

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"They have a small household and can fend for themselves. They’ll probably want to do that for as long as they can ... when you have butlers and nannies and cooks around, the house is no longer your own."

Were you surprised by any of these anecdotes?

You can read the full interview here.