(THE GUARDIAN) - Until very recently, common wisdom held that breakfast was the most important meal of the day.

We've anecdotally tied all sorts of ills to a failure to sit down to a "complete breakfast".

But health research has proven that skipping that fried egg or bowl of cereal does not, in fact, lead to weight gain, health issues or underperformance.

Our reverence for breakfast is actually relatively recent. Before the late 19th century in the US, breakfast didn't have any particular importance ascribed to it.

But all that was changed by a small group of religious fanatics and lobbyists for cereal and bacon companies.

Historically, breakfast did not come with its own list of prescribed foods, says Abigail Carroll, author of Three Squares: The Invention Of The American Meal . People simply ate whatever they had around for breakfast, which was often leftovers from the night before.

By the 1800s, what Americans think of as a farmer's breakfast started showing up at the table.

Eggs have always been a popular breakfast food, says Heather Arndt Anderson, author of Breakfast: A History. Chickens lay eggs in the morning, and egg dishes are easy and fast to prepare.

Meat that did not have to be slaughtered that day and could keep was also incorporated. Chicken was never a breakfast food, points out Arndt, as no one is going to kill a chicken first thing in the morning, but cured meat from a pig that was previously slaughtered could be.

In the late 19th century, however, people began to worry about indigestion as the Industrial Revolution saw people move from farm labour to factories and offices, where a lot of their time was spent sitting or standing in one place.

Heavy farm breakfasts before work got the blame for indigestion, a major preoccupation at the time, and a lighter version became the ideal.

It was around this time, in the middle of a general healthier living fad, that breakfast cereals got their start at sanatoriums founded by followers of the newly formed Seventh-Day Adventist religion.

These religious health gurus opened sanatoriums and introduced people to vegetarian diets and eating bland, whole wheat as a way to counter ill health. The first cereal, invented by James Caleb Jackson, and the better known Kellogg's brand, invented by John Harvey Kellogg, were both born at sanatoriums.

Jackson was a preacher, and Kellogg a religious man who believed that masturbation was the greatest evil, which bland, healthy foods like cornflakes could prevent. Both Jackson and Kellogg were early Seventh-day Adventists, further tying a sense of religious morality into their ideas around the importance of healthy eating.

Using moralising rhetoric to sell the idea of a healthy breakfast in the 19th century changed how people thought about the meal, says Carroll.

That moralisation was not just around religion and health: it also incorporated our reverence for hard work. In the early 20th century, the idea that if you ate a lighter, healthier breakfast you were going to be more efficient and productive at work added "another moralising layer", according to Carroll.

The cliche that breakfast is the most important meal - and one with very specific food groups - developed from those early days of cereal.

After vitamins were discovered, it did not take long before, in the 1940s, breakfast cereals were fortified and heralded as a source of every vitamin under the sun, making breakfast that much more important, according to advertisements at the time.

It was also around that time that women were entering the workforce in droves during the war, and needed something quick yet nutritious to feed the kids in the morning. Maternal guilt was used to market cereal as the best food to give to children, and underline the importance of eating breakfast.

It was a combination of fear of indigestion, religious moralisation and advertising that helped push the idea of breakfast as the most important meal of the day - but it was a campaign to sell more bacon that really solidified the idea. A public relations expert working for the Beech-Nut company, Edward Bernays, whose other claim to fame was being the nephew of Sigmund Freud, exploited all the moralisation and health fears around breakfast to help the company push its bacon.

Bernays got a doctor to agree that a protein-rich, heavy breakfast of bacon and eggs was healthier than a light breakfast, and then sent that statement to around 5,000 doctors for their signatures. He then got newspapers to publish the results of his petition as if it was a scientific study, explains Carroll.

That brought bacon and eggs back into fashion and added more weight to the idea that breakfast was not only very important but medically recommended.

Today, we are still mostly eating foods like cereals, bacon and eggs, rolls, bagels and croissants for breakfast. Dinner and lunch somehow never got the same treatment, and our adherence to the same narrow category of breakfast foods continues unabated.

It's not just the moralisation that got caught up with breakfast that has changed how we see it, says Arndt Anderson. Unlike lunch and dinner, there is something about the meal that lends itself to judgment.

"I think that the breakfast table is one place where you see the most blatant demonstrations of this human tendency to tie what one eats to who one is," says Arndt Anderson. "People make their lifestyle change at New Year and every morning is like a small New Year's Day - a chance to start things off in the right direction. So if you have cold pizza for breakfast, it says what sort of person you are."