To eat large amounts of food. A full-grown horse can eat up to 2% of its body weight per day, amounting to about 20 pounds of food. But, to be fair to the horse, an animal much bigger than one of us, it must eat a lot of grass or straw to get the same nourishment as a human might from a half pound of beef or a handful of walnuts.
In some cases, the phrase is a compliment while in others it’s an insult, depending on the situation. An allied phrase is “eat like a king.” The similar French expressions say “eat like an ogre,” or “eat as if one was four.”
The expression “work like a horse” dates at least as far as 1520, when horses replaced oxen and began to pull carts, carriages, and plows. Since horses were now partnered with humans in so many ways, perhaps “eat like a horse” came into use at the same time, though there’s no proof of this.
On July 12, 1882, the St. Joseph Daily Gazette in St. Joseph, Missouri published an article on Tug Wilson, the English pugilist. It described his training regime, including his intake of food. “He has hardened his muscles and reduced his weight most remarkably. He can now skip about like a squirrel, eat like a horse, and move about like a champion pugilist.”
In its August 9, 1920, edition, The Pittsburgh Press ran an advertisement touting the benefits of The Reese Formula R-11. It stated that a Mr. B. L. Allen, assistant foreman of the N&W Railway at Portsmouth, Ohio, claiming to previously suffer from “nervous indigestion and rheumatism,” had this to say about the product’s efficacy:
“I saw the medicine in the window at Fischer & Streich Drug Store and I decided to get a bottle and try it as I have always tried everything I saw. I am glad to say after taking two-thirds of the bottle I can eat like a horse, sleep like a country boy and feel like a 16-year old boy. If you wish to sue my name you are at liberty to do so. I will always recommend The Reese Formula R-11 to my friends.”
I wonder how much the company paid him. Or am I being too cynical?
I haven’t seen any more recent examples, and perhaps the phrase “I could eat a horse,” which means, “I’m really, really hungry,” is now more common. To say that someone eats like a pig is certainly more common, but also derogatory.
I’d be quite happy to eat like a horse. Since I love food, that would mean I could spend the whole day nibbling and enjoying myself.