Can you recall how many times you've heard or used the phrase ‘Don’t cry over spilled milk’? Probably not. Idioms are a way to say something ordinary in a more fun and colorful way. And it just so happens that many of the idioms we use the most are related to food. Considering how, throughout history, food has always played a central part in people's lives, this makes perfect sense.
Let's delve deep into history and travel all the way back to Ancient Rome to reveal the origins of 7 common food-related expressions in the English language.
We all have that one friend or relative who likes to think that they know more about a certain topic than they actually do. ‘I took their advice with a grain of salt,’ is what you might say when they try to give you some unsolicited advice. But where did that expression come from?
In the year 77 AD, the ancient Roman author Pliny the Elder wrote an encyclopedic book titled Natural History. In it, Pliny tells the story of a Roman general, Pompey, who encountered a king named Mithridates VI. The latter was known for having a strong immunity to poison, and Pliny shared the king’s recipe for his antidote. The last line read “to be taken fasting, plus a grain of salt.” Threats involving the poison were thus to be taken "with a grain of salt", or less seriously.
This phrase didn’t enter the English language until the 17th century and became common in the early 20th century.
Related: 15 Latin Phrases We Use to This Day Without Even Realizing
This may be one of the most popular and commonly-used idioms in existence. It is an old proverb, an earlier form of which is “no weeping for shed milk”. While the origin of the phrase isn’t certain, it is quite likely to have come from European folklore. 
Remember Pliny the Elder? Well, we can thank him for the expression ‘in a nutshell,’ too. In Natural History, Pliny writes about a miniature version of Homer’s The Iliad, written in a font so small that the whole book could fit inside... a nutshell.
Pliny’s anecdote seems highly unlikely because The Iliad is one long book, and in Homer's time, people wrote on clay tablets with the help of a stylus. This fact didn’t go unnoticed by one Philemon Holland, who had translated Natural History into English in 1601. Holland noted, skeptically, “The same writer maketh mention of one who could see to the distance of 135 miles.” Nevertheless, the association between compactness and nutshells had stuck, and it was even used in that very sense in Shakespeare's Hamlet.
In the context of the idiom ‘use your noodle’, the word noodle refers to one’s head or brain. This is interesting because none of those things resemble a noodle in any way. The use of the word may be related to the old term noddle, originally meaning ‘the back of the head’ in the 15th century.
Another related word is noggin, which could mean a cup or a person’s head, according to Dicitionary.com. Fun fact: in the past, ‘use your noodle’ was an insult, but nowadays, it’s considered a rather colorful way to ask someone to concentrate.
The phrase ‘It’s a piece of cake’ has quite a logical explanation. Since cakes are so delicious, they're easy to eat. But there is more to this popular idiom’s story. According to the Free Dictionary, the phrase it's a piece of cake originated in the Royal Air Force in the late 1930s, and it used to mean "an easy mission".
Another explanation is rooted in the African American community. In the late 1800s, a cake was a customary prize given in competitions, especially at events called ‘cakewalks’. In those contests, enslaved people performed a dance mocking the mannerisms of slave owners. The most graceful couple would receive a cake as a prize. This is also the source of such expressions as it's a cakewalk and that takes the cake.
