We seem to be reaching a cultural turning point around beef. People are rejecting beef because of their carbon footprint. This is *potentially* great. But it all depends on the substitution effects. 1/

Beef is worse than other animal products for the climate. But other animal products are worse than beef in other respects. For example, chicken is worse for animal welfare (because more animals are killed) and global health (because more diseases can spread). 2/

So, if we primarily care about climate change, then we might see replacing beef with chicken as harm reduction, and if we primarily care about other issues, then we might see the opposite as harm reduction. But both approaches simply trade some harms for others. 3/

This is why we need to think about food policy holistically. We need to think about animal welfare, global health, and climate change at the same time so that we can find ways to reduce harm across the board, rather than simply trade some harms for others. 4/

And when we think about food policy holistically, we see that harm reduction requires substituting animal-based foods for plant-based foods where possible. This is the best way to address animal welfare, global health, and climate impacts (among others) all at once. 5/

Since many people and institutions will be making food policy changes this year, we need to do everything we can to make this point about substitution effects salient. Yes, please, replace beef and dairy! But replace it with plant-based foods, not other animal-based foods. 6/

With all that said, I am extremely happy that this conversation is happening. Thanks to @epicurious for your decision to replace beef this week, and to everyone else for contemplating doing the same! This is how positive change happens. 7/