Kelly Swette and her husband Brian founded Sweet Earth Enlightened Foods seven years ago because they felt the market needed vegetarian food that was more convenient, flavorful and sustainable. As it turns out, they were at the leading edge of a booming trend.

Sales of plant-based foods are skyrocketing as consumers question the health and environmental impact of meat. U.S. sales of plant-based meat alternatives jumped 47% over the last three years; sales of traditional meat rose 3% in the same period, according to Nielsen.

Sweet Earth — which was acquired by Nestle in 2017 — makes more than 6...