I doubt that there is an entire journal dedicated to the relationship between breakfast and learning effectiveness.
If you are in school, go to the library and ask the librarian how to access the Cumulative Index of Nursing and Allied Health Literature data base, CINAHL. Your school probably has a subscription so you can access it for free. The librarian will also be thrilled to help you learn how to do efficient, effective searches, and no, although Google Scholar is helpful, life is not always about "Ask Google." Ask the librarian.
Your school likely also has a massive database of peer-reviewed journal articles that you should have access to via the library. Many hospitals also have libraries.
"Give a man a fish, and he eats for a day. Give a man a fishing rod and he eats for a lifetime." OP, don't think you can always get someone to find your articles for you and give you the links (though bravera has very nicely done so this time). Now you know how to do it yourself, go fish!
Does your school give you access to EbscoHost? I use it as a search engine anytime I need a professional article. It's a little difficult to navigate at first, but once you get the hang of it, reliable articles are easy to find. At my school, it is on the online learning page under library resources. You should double check to see if you have access!
That explains why it is always so easy to find journal articles r/t nursing! I like it as a resource because the content is credible with references. It's easier than "googling" because you don't have to weed out all the nonsense.