Meghan Markle will have to give up certain things while travelling abroad

The Duchess of Sussex won't be able to eat whatever she pleases while abroad

Even before she officially became the Duchess of Sussex, Meghan Markle had to make multiple lifestyle changes to adjust to life as a royal.

From deleting her social media accounts, wearing tights during public engagements, painting her nails in neutrals only and refraining from autographing anything with her impressive calligraphy, the Duchess of Sussex has had a lot to learn - and give up.

But while it may have been easy to leave behind dark nail polish colours, there is one thing the Duchess may find it harder to go without while travelling.

As a general rule, the royal family is banned from eating certain foods when dining out or in foreign lands.

While it may seem outdated to regulate what the royals can and cannot eat, the rules are mostly in place for their own safety.

With the couple's first royal tour approaching, this means that Markle will not be able to consume shellfish - due to the risk of food poisoning.

Although oysters are considered a delicacy by many, they actually carry a high risk of vibriosis - an illness caused by the bacteria Vibrio, according to the Centres for Disease Control and Prevention.

In November last year, it was reported that a deadly herpes virus, Ostreid herpesvirus 1, was threatening Pacific oysters, one of the world’s most popular species of oyster.

The couple will embark on their first royal tour in Autumn (Getty) (Getty Images)

Additionally, the Duchess of Sussex will have to refrain from eating rare meat and drinking tap water while she and her husband Prince Harry are visiting Australia, Fiji, the Kingdom of Tonga, and New Zealand.

As the newlywed’s schedule for their first royal tour is quite full, any food poisoning-related issues would only put a damper on the festivities.

Fortunately, Markle typically abides by a vegan lifestyle during the week - so avoiding shellfish and raw meat while abroad won’t be too difficult.

However, the Duchess of Sussex may have a harder time cutting onion and garlic out of her diet - a food ban that politely considers the amount of meeting and greeting expected from the couple.

The Duke and Duchess of Sussex will embark on their first royal tour in the Autumn.