Does the expression "breakfast is the most important meal of the day" come from a 1944 cereal marketing campaign?

Question

Eric Brown writes in How Marketing Created the Most Important Meal of the Day:

In 1944, a marketing campaign for Grape Nuts would be unleashed called “Eat a Good Breakfast — Do a Better Job”. During radio ads, it would be mentioned, “Nutrition experts say breakfast is the most important meal of the day.” This marketing phrase became soaked into our lexicon ever since. As you can imagine, this made the cereal industry powerful, giving them a monopoly over breakfast.

Is the claim that this marketing campaign is central for the belief true? Did the belief not exist before 1944 and was common afterward?

Answer 1

The expression predates that

These may not be the oldest examples (especially with so many variations of the expression), but these examples predate the radio entirely and even nearly predate Grape Nuts itself.

Saints Herald, 1887:

We commend the reading of the following; it contains a deal of good sense:
"EAT BEFORE YOU DRINK.
"A large proportion of intemperance in the use of stimulants," philosophized a physician, "may be laid to the light breakfasts eaten by most people. Breakfast is the most important meal of the day and sufficient importance is not attached to it in the majority of households."

That was reprinted in Good Housekeeping, 1889.

Donahoe's Magazine, 1897:

The breakfast is the most important meal of the day, and the thought and care bestowed upon its preparation will do much to make the day happy.

But opinions at the time varied

Nobody has ever thought that lunch was important (except maybe the French). Dinner, on the other hand...

The Illustrated Oarsman's Manual (1874?) says

Dinner, whether taken in the middle of the day or late in the afternoon, is the most important meal of the day.

When did it become popular?

Google Ngrams shows that growth of the expression was exponential, but 1944 was on the long tail of that. It saw a slight boost in the 1970s and took off in the 1990s. I didn't have time to sift through all the timeframe, but a cursory glance shows that it's the motto of several breakfast companies, such as Ovaltine. Kellogg's went a step further and funded research so they could push that conclusion.

Answer 2

Even within just cereal ads, the exact phrase "breakfast is the most important meal of the day" was used earlier for shredded wheat, for example in the below ad from page 19 of the Evening Star 27 February 1922.

Answer 3

I would argue that highlighting the importance of the breakfast meal is way older than what Laurel says. Since the question does not necessarily demand a science-based answer, I dare to quote some religious texts.

Based on the verse 19:62 of Quran (7th century CE):

They shall not hear therein any vain discourse, but only: Peace, and they shall have their sustenance therein morning and evening.

some commentators have speculated that breakfast and supper are the two most important meals, since God doesn't mention lunch. There are dozens of so-called hadiths that specifically recommend eating a proper breakfast. Such as this one from Ja'far al-Sadiq which roughly says:

After saying your morning prayers, bless yourself by eating some breakfast, because it cools you down and strengthens your teeth and jaws, and boosts your mood.

These kinds of hadiths along with some ancient books by the likes of Avicenna, are the basis of what is now called Islamic traditional medicine.

Answer 4

From Poor Richards Almanack (Benjamin Franklin) in 1739,

Rather go to bed supperless, than run in debt for a Breakfast.

I think this conveys the same idea of breakfast being the most important meal. And it probably indicates that it was a bit of popular belief that's been restated in different ways over the years.