There are countless little decisions behind every food choice we make: Is it healthy? Is it cheap? Is it available? Does it taste good? How hungry am I?

But there are two questions growing in importance and popularity at mealtime: Is this environmentally sustainable? and Is this humane? Rarely is the answer yes to both simultaneously.

That dilemma came up for me over the summer as I reported on McDonald’s decision to serve eggs from only cage-free chickens by 2025. Cage-free hens require more feed and have a higher mortality rate than caged. The trade-off—and there is always a trade-off—is that the caged hens have to spend their lives confined in pens whose length and width are roughly the size of a sheet of paper. At the time I described the dilemma like this:

Is it more humane for a bird to live in a cage or to experience liberty and die prematurely? And what is most humane is not always what is most productive—an especially relevant question as agriculture tries to feed a few more billion people by the middle of the century.

McDonald’s shift to cage-free eggs is part of a broader set of changes the company is making to its supply chain to appeal to a growing set of consumers who prioritize sourcing and provenance over fat and calories. Part of McDonald’s food makeover is a commitment to serve chicken without antibiotics “important to human health,” as the industry calls it. The company’s chickens are still regularly treated with an antibiotic called Ionophores, which are not used in humans. If a bird gets sick and needs a class of antibiotics important to human medicine, it is treated and removed from McDonald’s supply chain.

The antibiotics question—just like the cage-free issue—seems like it should be clear cut. It’s hard to find someone who disagrees with the idea that reducing the use of antibiotics is a good thing. But beyond that, the issue gets fuzzy—especially when considering what’s best for animals.

On one side of the antibiotics issue is a contingent that believes these drugs have been used as a crutch in industrial agriculture, which has allowed producers to raise animals in poor conditions. Eliminating the routine use of antibiotics forces farmers to improve the conditions in which animals live, argues Kari Hamerschlag, deputy director of the Food and Technology Program at Friends of the Earth. Sick animals should be treated with medications, she says, but even the regular use of Ionophores (which is part of McDonald’s policy) “potentially allows for not the best conditions.”

Another cohort disagrees. This group believes there’s an increased risk that animal welfare could suffer as more companies demand meat raised without antibiotics. “It’s not easy to raise an animal without antibiotics,” says Randall Singer, a professor of epidemiology in the department of veterinary and biomedical sciences at the University of Minnesota. “Live animals get sick.”

Singer is concerned that producers could resist treating sick animals in order to preserve their value. “I don’t believe that this massive tidal wave of ‘no antibiotics’ is good for anybody” if companies don’t have sound animal welfare policies in place, he says. “It’s a welfare question. Are we so willing as a society to say, ‘I’m more interested in what I think is healthy for me, but I don’t care as much about the welfare of the animal’?”

His last point is the key issue here. The reason many consumers don’t want antibiotics in their meat is because they’re concerned about antibiotic residue, which is regulated by the Food and Drug Administration and enforced by the U.S. Department of Agriculture’s Food Safety and Inspection Service. But what’s at the heart of McDonald’s and other companies’ policies is both a necessity and desire to reduce the use of these drugs so we maintain their effectiveness for when we really do need them. The more antibiotics are used, the more bacteria learn how to survive in the presence of these drugs and become resistant to them.

It’s more than reasonable—and I would argue a positive move—for consumers to add animal welfare and environmental impact as screens for their food choices. But these are far more complex measures than fat or calories. If we’re going to start prioritizing antibiotic-free meat or cage-free eggs, let’s at least understand what these terms truly mean.

Editor’s Note: This story has been updated to clarify comments from Randall Singer.