The story
Coined by John Harvey Kellogg, the inventor, and used as a brand name by the Sanitas Nut Food Company, Battle Creek Foods, and Worthington Foods. Apparently from protein + -ose.
Etymology from Wiktionary, CC BY-SA 4.0.
protose
Today it means: A meat substitute made chiefly of wheat gluten and peanuts, popular in the early twentieth century. Full definition →