Most people like to eat meat. Meat is nutritious. In particular, it packs much more protein per kilogram than plants do. But animals have to eat plants to put on weight — so much so that feeding livestock accounts for about a third of harvested grain. Farm animals consume 8 percent of the world’s water supply, too. And they produce around 15 percent of unnatural greenhouse-gas emissions.

All this has created a business opportunity. Though unwilling to go the whole hog, as it were, and adopt a vegetarian approach to diet, there is a market for food that looks and tastes as if it has come from farm animals, but hasn’t.

The simplest way to satisfy this demand is to concentrate on substitutes for familiar products.

Impossible Foods, a California firm, has deconstructed hamburgers, to work out what gives them their texture and flavor — and then either found or grew botanical equivalents to these. It launched its plant-based burger in a number of upmarket restaurants in America last year.

Beyond Meat, another plant-based hopeful, has compounded from legumes something that tastes like chicken. Last year, its “beef” patty reached the shelves of several stores belonging to the Whole Foods Market chain.

A second approach in the works is called “clean,” or cultured, meat — made by taking animal cells and growing them in a factory to form strips of muscle. Steak is not yet on the menu, but field leader Mosa Meat, a Dutch firm staffed by scientists, made its first burger in 2013 — at the cost of about $300,000. By 2020, it hopes, the price of making them will have come down to about $11.

Close behind Mosa, American start-up Memphis Meats is looking at the meatball. Between 2013 and 2015 it managed to bring its costs down a hundredfold — though even then a single meatball would have set you back $1,200.

Perfect Day, a start-up based in Berkeley, Calif., makes “milk” that has the same nutritional value and taste as traditional, dairy-based sources by engineering the relevant cattle genes into yeast cells, and growing those in fermentation tanks.

And there is one more novel source of meaty protein that does not involve farm animals in the conventional sort — insects. Already, 2 billion people around the world eat them.

The problem here is marketing. Grasshoppers are around 70 percent protein. It costs less to feed insects. The upside in this market might be using ground up bugs as ingredients. Hargol FoodTech, an Israeli start-up, plans to do just that. Locustburgers, anybody?