The saddest part of that is that I heard that phrase not through overt advertising but from school.
I remember a handful of occasions in elementary school where they had someone come in and teach kids about nutrition, and the one lady told us that breakfast is the most important meal because we need to start off our day with "lots of energy". These lessons included the food pyramid, which is bad science to start with.
As kids, we were being fed corporate propaganda through government sanctioned education, and sadly I don't think the students or any of the adults at the time realized it.
My favorite trick in this vein, now I believe defunct, is "doctors recommend starting your morning with a bowl of cereal".
The trick to that, of course, is the ambiguity of recommend'. You can ask a dozen doctors if a bowl of cereal with fresh fruit is healthier than nothing at all, or a bowl of plain oatmeal; if they say yes then they "recommend cereal". The same trick still works great for things like toothpaste, where a brand might be dentist-recommended not relative to the competition but to baking soda or plain water.
Page three is what you want, and it's worth looking at for a masterclass in garbage science.
The big header gives us "A cereal breakfast. Why it’s the best way to start the day." The subhead asserts "Experts worldwide agree: Breakfast is the most important meal of the day", which is somewhere between disputable and a lie. Below that is a list of wild claims like "People who regularly eat cereal tend to be less stressed, less anxious and are less likely to be depressed."
Wow! Let's see the evidence! Well, about half the studies listed appear to be directly funded by Kelloggs. Many that weren't are about breakfast in general, so "eat cereal" is a misrepresentation of "compared to skipping breakfast and eating unhealthy snacks". And they're full of hilariously poor controls - there's some fumbling with "difficulty sleeping" and a "negative job score", but ultimately the study can't discern "the benefits of eating breakfast" from "the harms of working the night shift" or "leaving at 5AM in a rush".
It's actually fascinating just how many bold, impressive claims Kelloggs manages to make without lying while relying on laughably thin evidence.
Dr. Kellogg and his brother had a business creating various supposed health products and Corn Flakes was part of that.
In 1917 a magazine called Good Health, edited by Dr. Kellogg, wrote "in many ways breakfast is the most important meal of the day". That seems to be the origin and cereal makers ran with it.
More importantly, Dr. Kellogg and his brother started two rival companies. The brother believed that sugar should be added to the formula Dr. Kellogg has been using to treat his patients.
Dr. Kellogg refused, believing sugar to be awful for the body.
Needless to say, we all know which of the two rival companies became the corporate giant, and which of the two rival companies disappeared into history. There was a big court case between the two rival brothers over the "Kellogg" name. After that, the two brothers never talked with each other for the rest of their lives.
Since the two were brothers, it is somewhat ambiguous to who really invented modern cereal. But Dr. Kellogg was the health-fanatic who would have been studying "healthy breakfasts" and other such stuff.
EDIT: It should be noted that 1890s / early 1900s medical science was downright awful. So definitely take any health claims from that era with suspicion. Be sure to look up "sanatoriums" and how awful their medical practices / beliefs were. There's probably a nugget of truth somewhere in Dr. Kellogg's research, but you've gotta look at his claims through the lens of history to really understand him.
The current insanity also grew out of commercials promoting the idea that you needed to spend big for this holiday. Historically, Christmas gifts were basically for children and poor people and the rest of it could be handled as a social get together based on a big meal and/or attending some kind of spiritual/religious thing. It wasn't some obligation to bleed yourself to participate in some out-of-control spending ritual in order to not be on the outs socially with everyone you know.
I remember a handful of occasions in elementary school where they had someone come in and teach kids about nutrition, and the one lady told us that breakfast is the most important meal because we need to start off our day with "lots of energy". These lessons included the food pyramid, which is bad science to start with.
As kids, we were being fed corporate propaganda through government sanctioned education, and sadly I don't think the students or any of the adults at the time realized it.