Down Arrow Button Icon

On-demand food delivery services are being pressured these days to do more than drop off burgers and fries. They must prove they can actually make money—a relatively new requirement for the industry that, for years, has lived large off of investors.

DoorDash, Uber Eats, Postmates, and Grubhub rapidly expanded as customers gobbled up the opportunity to have meals delivered to their homes for a nominal, and sometimes nonexistent, fee. But as the companies mature and venture capitalists tighten their purse strings, many wonder whether these venture-backed businesses will be able to continue their big-spending ways.

“Regardless of the unit economics, their launch and go-to-market strategy is almost entirely dependent on venture capital,” said Jordan Nof, managing partner of Tusk Ventures, which passed on investing in gig-economy companies. “Getting food delivered every day from whatever restaurant for lunch and dinner isn’t something, broadly speaking, that is sustainable in its current form.”

The shift in sentiment is a microcosm of the reduced appetite many investors have for risk. Following a big year of initial public offerings, some of which tanked, many investors have started to walk back their rapid-growth-focused investment strategies. Companies, especially those within the gig economy, are being held to a new standard: profits, and not just growth. And some on-demand food delivery services are starting to feel the squeeze.

Following lower third-quarter profits this year, Grubhub, one of the oldest competitors in the space, reportedly hired financial advisers to explore putting the company up for sale, according to the Wall Street Journal last week. Since the report, Grubhub has said that there is “no process in place” and “no plans” for a sale, even though it admitted that it always consults advisers about various issues including “potential acquisition opportunities.”

Meanwhile, Postmates delayed its IPO in October, blaming market conditions and providing fuel for speculation that the company is still hoping for a sale. A month later, Uber Eats announced plans to exit markets where it failed to become one of the top two players—a massive change from the previous serve-all-cities strategy it and most rivals had.

DoorDash, which has been rapidly expanding into new markets, has been relatively silent about its financial results. But based on reports that the company is readying for an initial public offering, the public soon may know more about its quarterly performance.

And even delivery services abroad are feeling the crunch. Deliveroo, based in the U.K., suffered a 2018 loss before certain expenses equivalent to $302 million—16% more than in the previous year. The company, backed by big investors including Amazon, reportedly needed a loan following a U.K. government probe into whether Amazon’s stake in the startup harms competition, according to Bloomberg. The latest loan, provided by Amazon and described as being of “significant” size, is expected to help Deliveroo continue its operations.

“What I know is, delivery is not profitable,” said Chris Webb, CEO of ChowNow, which provides software and support to restaurants for food delivery. “It’s been the same way since these companies started.”

The future of food delivery could play out a number of ways. Companies could refocus on dense, urban areas where they’re more likely to turn a profit because they could deliver more meals per trip, said Nof. They could also switch to offering more deliveries of fast food than restaurant meals, which, according to Webb, would help the companies lower their cost per delivery.

Additionally, delivery companies could sell themselves to larger corporations that are willing to take on losses like Amazon (even though Amazon shuttered its small food delivery service in June). Or, to earn more revenue, they could pivot into other services like renting space in shared kitchens.

In a worst-case scenario like venture capital drying up or the economy taking a downturn, some food delivery services may have to shutter.

At the very least, more consolidation is ahead, regardless of the economy.

Already, DoorDash completed its acquisition of Caviar, one of the smallest players in the food delivery field. But with Postmates, Uber Eats, and Grubhub, along with DoorDash, still in business, analysts expect to see more mergers within the next year or two.

If Grubhub were to sell, Uber Eats would be the most likely buyer, according to analysts at JMP Securities and J.P. Morgan. That’s because DoorDash and Postmates lack public equity as private companies, and therefore would likely need to raise more cash to afford it.

One thing that Grubhub has going for it, in addition to its size, is that it turned a profit during the first three quarters of 2019.

“That’s attractive for Uber as they march toward profitability,” said Ron Josey, JMP Securities analyst.

But even in the case of an acquisition, consolidation isn’t expected to end there. ChowNow’s Webb, who’s been participating in and monitoring the food delivery market for nearly 10 years, said he believes Postmates will also be sold.

“They’re likely going to have to sell themselves to someone who can take the losses or pare back and get to breakeven, which is a very hard task,” he said. “So they’ll likely get bought, but not for a whole lot of money.”

Josey expects companies will eventually curtail their expansions and discount fees, making it easier for them to become profitable. But Nof countered by asking how many customers would be willing to pay for food delivery that’s not subsidized by venture capitalists, particularly if there’s an economic downturn.

“This is the quintessential [example of] applications solving problems that really don’t exist,” said Nof. “This is nice to have; this is not something we need to have. These are convenience factors.”

No more free lunch: Food-delivery services feeling pressure to finally turn a profit

More must-read stories from Fortune: