The simple answer is “I don’t know” and nor do any of the public health bodies/obesity organisations that use it, as this post comprehensively confirms. The “Prove it or stop using it” post invites anyone to source/prove the calorie formula. The challenge was first thrown out in my 2010 obesity book and still goes unanswered.
This post is to share the earliest reference that I have found to the formula (although it doesn’t actually state it). I’d be very interested in anything earlier that anyone can find and even more interested in proof. There is enough counter evidence already that I can guarantee that proof cannot and will not be found.
Lulu Hunt Peters (1918)
In a book called Diet and Health by Lulu Hunt Peters (1918),[i] Hunt Peters states “Five hundred Calories equal approximately 2 ounces of fat. Two ounces per day would be about 4 pounds per month, or 48 pounds per year. Cutting out 1000 Calories per day would equal a reduction of approximately 8 pounds per month, or 96 pounds per year.”
An article from the Chicago Daily Tribune (Sept 15, 1959) asserts “a pound of fat is lost whenever the body burns up 3,500 calories by diet or exercise”.[ii] The way that this is asserted, suggests that it is already a well known ‘fact’ by this date, but did Hunt Peters start it or perpetuate it?
A couple of extracts in Diet and Health make me think that it is plausible that Hunt Peters did effectively originate “The Calorie Formula”:
1) On the opening page, Hunt Peters says: “I am sorry I cannot devise a key by which to read this book, as well as a Key to the Calories, for sometimes you are to read the title headings and side explanations before the text. Other times you are supposed to read the text and then the headings. It really does not matter much as long as you read them both. Be sure to do that. They are clever. I wrote them myself.” (Hunt Peters own emphasis in italics).
2) Chapter 2 “Key to the calories” has the following: [Sidenote: Pronounced Kal’-o-ri]. So calories were so little known at the time, that Hunt Peters needed to tell people how to pronounce them. If only we had stayed so blissfully ignorant about calories, or at least had come to see them as fuel for the body – which is all that they are.
If Hunt Peters had the right to be proud of her ‘cleverness’ and if she really did break something revolutionary to the women of Los Angeles in 1918, we may indeed have one woman to ‘thank’ for “The Calorie Formula”, which is the foundation of weight loss advice to date. If anyone else knows of a reference earlier than 1918, I would be most interested for research sake, but it actually matters less from where this originated and more that it has held as ‘fact’ for almost a century and yet it cannot be proven to hold true.
p.s. I know the background to the estimated calories per gram (which are wrong) and how the 1lb is assumed to be 3500 (which is also wrong). I’m looking for the first reference to the calorie formula/theory (the two parts being: 1lb = 3500 cals; to lose 1lb you need to create a deficit of 3500 cals) or an earlier application of the theory – without actually stating it – than Lulu Hunt Peters. It’s a very specific statement, which has pervaded virtually all dieting literature and which millions, if not tens/hundreds of millions of people are following right now. And we know not from whence it came!
[i] Lulu Hunt Peters, Diet and Health (with key to the calories), published by Chicago The Reilly and Lee Company, (1918).
[ii] T R Van Dellen, “How to keep well”, Chicago Daily Tribune, (15 September 1959).