The earliest use of the term "plant-based diet"

The term "plant-based diet" is popular. And it's used with all kinds of different meanings - and this isn't the topic of this post.

The other day I saw that on Wikipedia, on the page for "Plant-based diet", it says:

"Origin of the term 'plant-based diet' is attributed to Cornell University nutritional biochemist T. Colin Campbell who presented his diet research at the US National Institutes of Health in 1980." (as of 14 February 2023; the reference given is a New York Times article, just saying - not that I would recommend reading that newspaper).  

Now, this T. Colin Campbell is of course the author of the well-known, widely read and for some reason beyond my understanding popular in the "vegan" movement (it's a book full of animal experiments conducted by the author).

While in the English version the Wikipedia article says that the origin "is attributed to" (see quote above), the German version of the Wikipedia article on "Plant-based diet" says something more like "T. Colin Campbell claims to have coined the term plant-based diet" (as of 14 February 2023).

I'm not too interested in what anyone claims. But I was curious to check if, by doing a few simple searches, I could easily find an earlier (before 1980) use of the term "plant-based diet".

And I did find several.

Of course, T. Colin Campbell might have coined the term earlier than when these articles were written. But that seems quite unlikely. 

Below are several early (before 1980) uses of the term "plant-based diet":


1976

N. H. Anderson: "Carnivory by an Aquatic Detritivore, Clistoronia magnifica (Trichoptera: Limnephilidae)", published in August 1976 in the journal "Ecology". https://doi.org/10.2307/1941074
The article is about an insect species (a type of caddisfly - the article describes an animal experiment). In the article it says: "[...] The experiments reported herein were designed to determine whether the quality or vigor of laboratory cultures of the caddisfly Clistoronia magnifica (Banks) could be improved by augmenting a plant-based diet with some animal food. [...]"
The diet given to the caddisflies contained alder leaves, conifer needles, wheat grains, and green grass - a "vegan" diet you could say. And then the scientist/s added some "animal food" in the form of live (I think) small white worms (Enchytraeidae) as "prey" for the caddisflies.


1977

Constance Kies and Hazel M. Fox: "DIETARY HEMICELLULOSE INTERACTIONS INFLUENCING SERUM LIPID PATTERNS AND PROTEIN NUTRITIONAL STATUS OF ADULT MEN", published in March 1977 in the "Journal of Food Science". https://doi.org/10.1111/j.1365-2621.1977.tb01518.x
This article describes a human intervention study. The article states: "The objective of the present project was to determine the effect of graded levels of hemicellulose added to a constant, plant-based diet on serum lipid patterns and protein nutritional status of adult men. [...]
[...]
[...] The purpose of the present study was to investigate the effect of graded additions of hemicellulose to a plant-based diet on serum lipid patterns and protein nutritional status of adult men. [...]"
Check Table 2 (see picture) for what they meant by "plant-based diet":
I'm not sure what they meant with "bouillon", but it could have been a meat-based bouillon.


Mary L. Duke, Constance Kies, and Hazel M. Fox: "NIACIN AND PANTOTHENIC ACID EXCRETIONS OF HUMANS FED A LOW-METHIONINE, PLANT-BASED DIET", published at some point in but probably towards the end of 1977 in the "Journal of Nutritional Science and Vitaminology" (Tokyo). https://pubmed.ncbi.nlm.nih.gov/611157/
This article describes a human intervention study. Under Table 1 and Table 2 you can see what they meant by plant-based diet in the context of their study: "Diet pattern consisted of meals of the following: peanut butter (90.7g), butteroil (varied), starch bread (one recipe), tomato juice (100g) applesauce (100g) peaches (100g), pears (100g), green beans (100g), jelly or honey (varied), tea (limited to 1tsp. dried instant/day) or coffee (limited to 3tsp. instant dehydrated/day)." So, it was a mostly vegan diet, I would say.


Minoru Yoshida: "Potassium Deficiency of Chicks and Rats fed Bacteria Grown on Methanol", published in November 1977 in the journal "Japanese Poultry Science". https://doi.org/10.2141/jpsa.14.266
As you can see from the title of this article, it describes an animal experiment. The article includes this sentence (and no other mention of "plant-based diet"): "[...] The requirement of potassium for poultry should be re-examined carefully, although this may not be meaningful under the practical condition, since feeding plant based diet are usually rich in potassium. [...]" [!]


1980

In 1980, there are also some more interesting papers that include the term "plant-based diet", namely two articles by Jeanne H. Freeland-Graves et al.:
"Alterations in zinc absorption and salivary sediment zinc after a lacto-ovo-vegetarian diet", August 1980, https://pubmed.ncbi.nlm.nih.gov/6250397/
"Zinc status of vegetarians", December 1980https://pubmed.ncbi.nlm.nih.gov/7440860/