Want People to Eat More Plants? Make Them the Default.

Making vegan foods the default option consistently boosts sales without significant backlash. Here's the evidence why it's so effective.

In the developed world, meat is considered the default option. Waltz into most restaurants and it’s plain to see that main dishes feature oodles of animal products while plant-based foods are relegated to side dishes or even a separate menu. Airlines require passengers to opt into eating plant-based food onboard, usually ahead of time. Conferences, catering, delivery apps, dining halls… they all require consumers to put in just a little extra effort to eat meat-free. But we might be able to reverse that.

Plant-based defaults are a food service system in which vegan and vegetarian options are presented as the default. Customers can still eat meat! They just have to put in a little extra effort to do so: say, ordering ahead of time or talking to a staff member. This small change has a strong effect. The research shows that plant-based defaults (PBDs) are the most impactful nudge we know about — powerful enough to sway consumption trends but not controversial enough to inspire significant resistance. Let’s dive into it.

This is my final post on the effectiveness of plant-based nudges — check out my earlier editions on vegan labelling, plant-to-animal ratios, and supermarket design. If you want to stay up-to-date on the research behind effective animal advocacy, you can subscribe to this newsletter.

Making Plants the Default Option Works Wonders

What does a plant-based default look like in practice? It depends on the location. At conferences or events, guests may be automatically offered the veg option unless they fill out a form to switch to an animal-based meal. In cafeterias, buffets, and dining halls, customers may need to ask staff to fetch meat dishes from the back while plant-based options are front and center. In restaurants, defaults are a bit tricky but still doable. The dishes may be plant-based by default, with customers able to add animal products for an extra charge. Think a burrito with soya meat, which you can swap for chicken for an extra three bucks.

Here´s what a plant-based default looks like in a college dining hall (taken from this study):

Note how the meat dish is still available in the plant-based default (photo B), but students will have to ask the staff to fetch it from the back. This small extra effort will deter many students from ordering the less sustainable meal.

And boy, oh boy, does this work. Across the board, defaults are the most consistent way to influence plant-based eating in dining institutions. Full stop. Not only have several studies found them to be the best nudge available, but my own research shows their power quite clearly:

To review all the studies in detail, click here.

Across all the studies I could find, when meat is presented as the default option, consumers order vegan meals around 19% of the time. When plant-based options are the default, that number skyrockets to 69%. That’s an increase of a factor of 3.7. To put it bluntly: most interventions to reduce meat consumption are not this consistent, nor this powerful.

Many other meat reduction interventions aim to persuade people to make more ethical, sustainable, healthful, or conscious choices when dining out, but they don’t always work because people don´t always make decisions consciously. The beauty of a plant-based default lies in its simplicity — since most consumers go with the flow when ordering food, let’s change the tide rather than make them swim upstream.

Working With Institutions To Implement PBDs

There are many benefits to a plant-based default that aren’t just related to meat consumption. For starters, plant-based food is usually the most inclusive option — it allows vegetarians, vegans, people who follow kosher or halal diets, Jains, Hindus, Buddhists, lactose-intolerant individuals (which is most people by the way), and people with egg allergies to eat freely.

It can also save money! As I’ve written about previously, vegan diets are typically cheaper than animal-based diets, so it stands to reason that plant-based defaults can save on procurement costs. One study of New York City hospitals found that the plant-based default meals saved 59 cents per plate. And, of course, because plant-based food is more sustainable, plant-based defaults can reduce climate emissions, up to 42%.

One of the beautiful things about PBDS is that, with multiple benefits, there are many ways to approach stakeholders: public events with diverse audiences may want to be more inclusive with food options, while colleges with climate commitments can show how they’re reducing emissions.

These policies are more popular than you might think. Since plant-based defaults don’t remove choice, most consumers are more open to PBDs than an entirely plant-based menu. It makes sense! Anyone who truly craves meat would order the meat option rather than complain to the staff. When researchers survey diners in a plant-based default, they don’t find that anyone is angry or upset about the change.

One study found that consumers are more accepting of plant-based defaults than restaurant managers are, suggesting that managers are too concerned about public blowback. Thankfully, that blowback is rare: most PBDs have satisfaction rates above 90%. These policies are popular; it’s just about getting institutions like colleges, hospitals, public events, and more to buy into them.

Long-Term Impacts of Plant-Based Defaults

College dining halls are where defaults may work best, since they may offer benefits beyond just short-term meat reduction. Campuses are hubs for young adults learning about social norms and practices, so if we can make plant-based eating extremely normalized for huge cohorts of young people, it can have ripple effects for generations. I couldn’t find research proving that PBDs can influence social norms, but I suspect they can. I’d love to see more researchers study this.

There is a problem with diner retention — some studies have found that potential consumers may not attend the dining halls when a plant-based default is instituted, and instead eat meat at another establishment (researchers call it the ‘spillover effect’). Two studies reported pessimistic data: one found that instituting a plant-based default correlated with a 26% reduction of overall sales, while another found that instituting a meat-free day was associated with a 17% sales decrease.

Since very few studies actually check for spillover, I looked at the data tables from other studies and did some back-of-the-napkin math to discover how big a problem spillover really is. In one study, college students ordered 20% more meals when a plant-based default was implemented, compared to a standard meat default. To me, it remains an open question whether an adverse spillover effect exists and, if so, how big a problem it is.

Even if a spillover effect exists consistently, it is likely smaller than the intervention´s benefits. In other words, fewer people skip eating at the PBD station than people who switch from meat to vegan, so the number of people eating plant-based food still rises.

Tracking the Spread of Plant-Based Defaults

Overall, PBDs are highly effective in reducing meat consumption and are less likely to incur blowback or criticism than many other interventions. As long as they’re implemented well, we can minimize potential spillover effects and maybe even shift social norms around how we eat.

I’ve been researching interventions to reduce meat consumption for years now. I can say confidently that plant-based defaults are the initiative that excites me most. It’s that perfect combination of palatable, scalable, and impactful work that can really move the needle.

I’m hoping my series on behavioral science has helped you think more about these interventions! But that’s not the only reason I wrote this — I am working on formally tracking these interventions to show how effective they are, give credit to the organizations that work on them, and demonstrate how this social movement is progressing. If you know of a plant-based default or nudge in your area, please fill out this form to help track it (it takes 2-3 minutes!):

Thank you

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