American author and nutritionist Adelle Davis (1904-1974) suggested that a proper diet should have bigger breakfasts (when energy is needed throughout the day) and lighter dinners. “Eat breakfast like a king, lunch like a prince, and dinner like a pauper” was her nutrition adage that was printed in her book, Let’s Eat Right to Keep Fit (1954).
 
“Butter is gold in the morning, silver at noon, and lead at night” is a related and much older proverb,  printed in The Haven of Health (1584) by Thomas Cogan, among many other books. Adelle Davis changed the “gold, silver, lead” to “king, prince, pauper.”
 
     
Wikipedia: Adelle Davis
Adelle Davis (25 February 1904 – 31 May 1974) was an American author and nutritionist, considered “the most famous nutritionist in the early to mid-20th century.” She was as an advocate for improved health through better nutrition. She wrote an early textbook on nutrition in 1942, followed by four best-selling books for consumers which praised the value of natural foods and criticized the diet of the average American. Her books sold over 10 million copies and helped shape America’s eating habits.
 
Despite her popularity, she was heavily criticized by her peers for many recommendations she made that were not supported by the scientific literature, some of which were considered dangerous. She was the first woman nutritionist of healthy feeding and “health authorities” who obtained a professional background in dietetics.
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Quotes
Adelle Davis is known for:
 
“Eat breakfast like a king, lunch like a prince and dinner like a pauper.”
             
Early English Books Online
The Haven of Health
By Thomas Cogan
London, UK: Printed by Anne Griffin
1584
Pg. 180
Of both sorts of creame is made Butter, which if it be fresh and newe made, is verie wholesome, especially if it be eaten in the morning, but afterward it is not so good, according to the old English proverbe, Butter is Gold in the morning, and Silver at noone, and Leade at night. The meaning whereof because it is so common, I will here omit. The chiefe properties of Butter are recokoned to be three in Schola Salerni as followeth.
 
Google Books
A Practical and Polemical Commentary:
Or, Exposition Upon the Third and Fourth Chapters of the latter Epistle of St. Paul to Timothy
By Thomas Hall
London, UK: Printed by E. Tyler
1658
Pg. 334:
We may say of many Ministers as they say of Butter, ‘tis gold in the morning,filver at noon, and lead at night, ...
   
Google Books
Lexicon Tetraglotton, an English-French-Italian-Spanish Dictionary
By James Howell
London, UK: Printed for J. G. by Samuel Thompson
1660
Pg. 7 (English Proverbs):
Butter is gold in the morning, silver at noon, and lead at night. Le beurre est or au matin,argenta midy, & plomb au soir.
 
OCLC WorldCat record 
Let’s eat right to keep fit
Author: Adelle Davis; Harcourt, Brace & World.
Publisher: New York : Harcourt, Brace & World, © copyright 1954.
Edition/Format:   Print book : English
 
2 December 1954, Spokane (WA) Daily Chronicle, “King-Sized Breakfast Best, Nutrition Expert Declares,” pg. 3, col. 7:
Eat breakfast like a king, lunch like a prince and dinner like a pauper if you want lots of energy and don’t want to be fat.
 
That’s the advice of Adele Davis of Los Angeles, nutrition consultant of author of “Let’s Eat Right to Keep Fit,” “Let’s Have Healthy Children,” “Let’s Cook It Right” and other books on nutrition.
 
Miss Davis was in Spokane this morning en route to Cheney, where she spoke on nutrition to students at Eastern Washington College of Education.
 
2 September 1955, Kingsport (TN) News, pg. 1-B, col. 1:
Breakfast Is
Most Important
Meal Of Day
MIAMI BEACH, Sept. 1 (INS)—Breakfast may be of fleeting concenr to persons dashing to work in the morning but, according to a noted nutritionist, it should be the most important meal of the day.
 
That was the advice given today by Adelle Davis, an author of several books on nutrition, to a convention of the National Dietary Foods Association at Miami Beach.
(...)
Her general rule, she said, is to “eat breakfast like a king, lunch like a Prince and dinner like a pauper.”
   
4 December 1956, The Washington Post and Times Herald (Washington, DC), “Keep In Trim: Breakfast Like a King ” by Ida Jean Kain, pg. D3, cols. 1-2:
One doctor expressed it this way: To reduce, breakfast like a king, lunch like a prince, and eat like a pauper at dinner.
 
Google Books
Sex and the New Single Girl
By Helen Gurley Brown
New York, NY: B. Geis Associates
1970
Pg. 164:
Eat breakfast like a king, lunch like a prince, supper like a pauper (except on a date), not the other way around.
     
Google Books
Medically Speaking:
A Dictionary of Quotations on Dentistry, Medicine and Nursing
By Carl C. Gaither and Alma E. Cavazos-Gaither
Philadelphia, PA: Institute of Physics Publishing
1999
...eat breakfast like a king, lunch like a prince, and dinner like a pauper.
Let’s Eat Right to Keep Fit
Chapter 2 (p. 19)
 
Google Books
Nutrition and Health in the Bible
By Kathleen O’Bannon
Nashville, TN: Thomas Nelson
2008
Pg. CXVII:
The mother of modern nutrition, Adelle Davis, used to say: Eat breakfast like a king, lunch like a prince, and dinner like a pauper.
 
Google Books
Positive Mind, Healthy Heart
By Joseph C. Piscatella
New York, NY: Workman Publishing Company, Inc.
2010
Pg. 217:
As noted nutritionist Adelle Davis advised, “Eat breakfast like a king, lunch like a prince, and dinner like a pauper.”
 
Google Books
Oxford Treasury of Sayings and Quotations
Edited by Susan Ratcliffe
New York, NY: Oxford University Press
2011
Pg. 89:
Breakfast like a king, lunch like a prince, and dine like a pauper.
recommending lighter meals as you move through the day; modern saying
 
Google Books
The Weight Loss Bible:
A Scientific Approach to Lose Weight and Keep It Off
By Zachary Zeigler Ph.D.
Bloomington, IN: iUniverse
2018
Pg. ?:
“Eat breakfast like a king, lunch like a prince, dinner like a beggar” -Unknown