A promising class of startups believes the solution is not to ask eaters to give up meat but instead to make actual meat more sustainable and alternatives more convincingly meatlike. And the companies are turning to cutting-edge food technology to do it.

To satisfy beef cravings, Impossible Foods has developed a plant-based burger that looks, tastes, and behaves uncannily like one made from the real McCoy. Its secret is heme, an iron-rich molecule that gives meat its meaty taste. Heme can be found in the roots of nitrogen-fixing plants, but Impossible Foods determined that it was more economical and sustainable to make it through industrial fermentation—a process by which it transfers a gene from the soybean plant into yeast, grows the yeast, and then isolates heme in the resulting broth.

In the seafood department, startup AquaBounty has received approval from the U.S. Food and Drug Administration for fast-growth salmon that have been genetically engineered to get to market weight in about half the time as unmodified fish. And for poultry needs, Memphis Meats is commercializing what it says is the “world’s first chicken produced without the animal.” The company grows meat in tanks by feeding living animal cells oxygen, sugar, and other nutrients. The process uses about 1% of the land and 10% of the water needed for conventional animal agriculture.

A complicating factor in all of this has nothing to do with the science. It’s that the target market for these products—people who care about the carbon footprint of what they eat—is also resistant to mixing technology with food (e.g., the backlash against genetically modified organisms). These promising startups will have to convince consumers not only that their food tech isn’t scary, but that it may be the only way they can have their meat and eat it too.

This article is part of “The Future of Startup Innovation” package that appears in the May 1, 2017 issue of Fortune magazine. Click here to read more from the series.