Tactics In Practice: The Science Of Plant-Based Defaults And Nudges
Welcome to the second addition to our Tactics in Practice series, where we dive into the effectiveness and strategies of different interventions. On today’s menu: nudges, default veg, and food labels!
What Are Nudges And Defaults? And How Do They Work?
Many of our daily decisions aren’t the result of purposeful thought or deep consideration—but rather choices that emerge from our habits, social and physical environments, and psychological biases. Nudge theory posits that by changing the choice architecture of our decisions, we can promote better behaviors at a large scale.
In practice, imagine moving all the healthy food to the front of your refrigerator (choice architecture) to hopefully nudge you into reaching for an apple for your midnight snack instead of something you’re trying to avoid. That’s a nudge. This strategy has many advantages, not the least of which is that it doesn’t completely remove choice itself (i.e. customers aren’t throwing away all of your junk food overnight), so it’s less likely to cause major grumbling. This represents a key opportunity for animal advocates — nudges can help everyone make more pro-animal choices in their day-to-day lives without major pushback.
The key audience for nudges is not vegans, vegetarians, or strident meat-eaters, but flexitarians. This group could also be called the “persuadables” — a group of roughly 62-75% of people who, according to Pax Fauna research, are less motivated by ethics and more susceptible to social norm shifts (among other appeals).
Before we jump into the science, let’s define some key terms.
- Plant-based default (PBD): In a PBD, the vegan option is positioned as the default option with meat only available upon request. This can be done in various ways: putting meat dishes on a secondary menu for a restaurant, not serving meat visibly in cafeterias, adding a surcharge for adding meat to a vegan dish, or having people opt into meat while signing up for a conference buffet. You may have also seen the terms “Default Veg” (which is an initiative of the Better Food Foundation), or “Plant-Based by Default.”
- Choice Architecture: This psychological term refers to the way choices are presented to people. For example, when a grocery store places more profitable items at eye level, and less profitable items close to the floor, they structure consumer choice for their own advantage. For advocates specifically, this can refer to menus, cafeteria design, and labels, among others.
- Nudge (or plant-based nudge): A nudge is a broader term for any subtle way of influencing a consumer to choose a plant-based option. This can include the format of a menu, the physical space of a food service area, the phrases used by cafeteria staff or waiters, and much more.
- Ratios (or plant-based ratios): This term refers to the ratio of veg options to meat options in a menu; a ration nudge may include adding far more veg options to a menu, hoping that more choices will result in fewer meat dishes served.
- Menu Engineering: Refers to the way a menu may frame options to make the plant-based option more appealing by changing language, placement, description, photos, and more.
As part of writing this blog, we spoke to six advocates working on these interventions, primarily in the United States. While campaigners for PBDs tend to be motivated by animal ethics, stakeholders, such as food service managers, may be swayed by other arguments, including inclusivity towards those with dietary restrictions, sustainability, or demand (especially from students). Advocates are especially interested in universities, as influencing younger generations is a key strategy for the movement and, based on anecdotal evidence, universities are often open to making these changes.
PBDs often, but not always, depend on internal allies — people working in offices or cafeterias who want to be more sustainable, or who may or may not be themselves vegans. This represents a key advantage of the programs: they can be easily embraced by people outside the movement who see the value in their basic premise.
How Effective Are Plant-Based Default Programs?
Implementing a PBD option in a dining hall (in which meat is present but has to be specifically requested) seems to be a slam dunk. Across nearly a dozen studies, such programs were able to significantly increase the portion of veg meals ordered and eaten — of the successfully-executed PBDs (see our explanation after the chart), the average increase of vegan or vegetarian option selected jumped from an average of 17.2% to an average of 72.5% – over a three-fold increase. While writing this resource, we were unable to find evidence of a correctly-executed plant-based default program that failed to reduce the amount of meat consumed.
Note: These studies differ in their methodology, population, meals, and location — thus the chart is not intended to represent an apples-to-apples comparison of studies but rather an apples-to-meat comparison: to show the overall trend that plant-based defaults increase the amount of veg meals orders.
We excluded one experiment from this analysis because the implementation was too poor to be considered a default: inconsistent signage, reports of servers guiding students to choose meat, and most importantly, meat being visible next to the plant-based option. With this incorrect implementation, the effect disappeared. Secondly, all of these studies were conducted in the U.S. or Europe and we weren’t able to find any research of default programs in other regions — meaning we don’t yet know if this effect would be the same in other parts of the world.
However, we must be aware of spillover effects — for example, when instituting a PBD in one station, some university students might just walk over to another station. We only found two PBD studies that calculated a spillover effect, and they were rather similar: 26.3% and 26.1%. In other words, when the station implemented a PBD, around a quarter fewer students ordered a meal from there. Thankfully, the calculated spillover effects were smaller in both studies than the increase of veg orders – in other words, less meat was still served at the PBD stations. Still, advocates should be mindful of any spillover effect and do their best to mitigate it (see our tips below for some ideas).
But what about the long term? For example, if a student goes to a plant-based default university cafeteria for four years, are they more likely to go (or stay) vegetarian, vegan, or flexitarian later in life? If so, plant-based defaults would have an even larger capacity to impact animals. At this point, we don’t know for sure. Nudges work, in part, because they influence social norms, and since social norms are critical to creating and maintaining vegans, some behavioral scientists believe PBDs can create long-term diet change, but others are less certain.
It’s worth noting that nudges and defaults don’t work well on everyone. Multiple studies have found that nudges are most effective for people who are already reducing their meat consumption (flexitarians or reducetarians) or people who are already environmentally- or health-conscious. Nudges may also work better on women than men (although this may just be because women are more likely to be flexitarian than men).
One thing that frequently came up in our conversations is that advocates need to be willing to compromise. If a PBD isn’t on the table, increasing the number of vegan options on the menu without making them the default can also be an effective strategy. In fact, doubling the plant-based ratio can increase veg meal selection from between 41% and 79% while increasing the ratio from 25% to 75% increased their popularity from 12% to 48%. Improving the menu engineering, often by revamping the labels of vegan meals, was also found to be somewhat effective in promoting individual menu items (discussed in more detail below).
Given that not all stakeholders are going to be on board with a plant-based default, the chart below can help advocates consider what compromises may be the most tractable.
Since nudges can vary so much, below we review research findings for some of the most common types of nudge-based situations.
Restaurants and Supermarkets
While most advocates we spoke to tend to focus on universities, restaurants and supermarkets are also avenues for change.
Location and placement are everything in a supermarket. Beyond Meat famously prefers that all their products be sold in the meat sections of a supermarket, as opposed to a “vegan” or food allergy section. This is likely wise — one study found that vegan alternatives sold 67% better in the butcher sections, right next to animal-based meat, as opposed to being in their own areas. Meanwhile, placing healthy foods, which could include vegan products, near the check-out counter increased their sales by almost 50%.
PBD programs can also be added to restaurants. One way is to offer meat as an addition to a plant-based menu item — for example, a veg burrito which chicken can be added to, rather than offering separate veg and chicken burritos. In one online study that tested multiple ways to maximize vegetarian menu items, that strategy won out. For a real-world example, our restaurant case study found that the veg orders increased by 13% over five years, possibly due to a default veg policy they implemented for all but one of their breakfast sandwiches.
Other nudges and labels can still be helpful in a restaurant setting. One of the easiest-to-implement changes is to simply get rid of a separate “vegetarian” or “vegan” menu section altogether and mix those dishes into the rest of the menu — a move that could raise their orders by 56%, according to one study.
The advocates we spoke to told us they don’t often prioritize restaurants as they are more likely to be motivated by profit and less likely to be motivated by sustainability. If you are interested in working with a restaurant to add nudges to their service, keep in mind that you may need to change your messaging strategy to communicate how these changes may help improve profits, or only target restaurants that are openly climate-conscious.
Benefits For Animals AND Institutions
Instituting a well-planned default may also end up saving money. According to an analysis of the implementation of plant-based food options in New York City hospitals, the vegan options saved about 59 cents per meal by using whole food plant-based ingredients.
All of this reduced meat consumption helps the planet — multiple studies confirm that using plant-based defaults reduced the climate impacts of dining halls. One study found the greenhouse gasses savings by the plant-based default program to be about 23.6%, while another analysis in New York pegged the number at 36%. Yet another estimated it to be 40.1%, while a third found the drop to be 42.7%.
Aside from the bottom lines and carbon footprints, these initiatives are often quite popular. In two reports — the New York hospital initiative and a set of experiments in Denmark — plant-based initiatives had an approval rating of 90% or higher among participants. An internal survey from the Changemaker Hub, reviewed by Faunalytics, on students at cafes with a plant-based default shows only a minority of students disapprove: just 7%. Another study found that across three universities, students’ enjoyment of a given plant-based dish increased when it was made a default, surpassing even the enjoyment of meat dishes. And in an online study, participants’ willingness to eat out at a restaurant didn’t significantly change when strong plant-based nudges and defaults were added to the menu.
Plant-based default programs have the unique advantage of being mutually beneficial to nearly every party involved: the advocates, the stakeholders, the consumers, the environment, and, of course, farmed animals.
How Can Nudges Be Improved?
While nudges are effective in reducing meat consumption, they can always be improved. Here are our research-backed tips on how to ensure your nudges are as effective as possible.
Train Your Staff Well
As we mentioned above, one study found that when a plant-based default isn’t instituted correctly, people will still order the same amount of meat-based options. In the above instance, the reason for the subpar execution was likely due in large part to understaffing and poor server training. The cafeteria workers did not properly display the food options and the signage, and even occasionally talked negatively about the plant-based options, which likely harmed the impact of the PBD.
One advocate we spoke to specifically mentioned that they wished they were more upfront with their university about the training required — without proper buy-in, cafeteria staff won’t be able to implement the program well. Make sure to have honest, open conversations with staff about your default veg or nudge intervention. Listen to their input, answer their questions, and make sure everyone knows they are on the same team.
Pay Attention To Labels
Many animal advocates likely know to avoid the dreaded v-word (pssst…it’s “vegan”). Overall, most studies we reviewed showed that items labeled “vegan” were chosen less frequently than others. Some winning alternatives from the literature include the simpler “healthy”, “sustainable” to the more creative “Environmentally Friendly Main Courses for a Happy Planet” (which uses wording to invoke both sustainability and positivity), or “juicy American burger” (which pinpoints the texture and origin of the food).
Apart from those options, you can instead focus on describing how the food tastes! A pair of studies that measured the effectiveness of highlighting food’s taste over healthfulness found that taste won out by a fair margin: a taste-focused label improved the item’s selection by 38% and 29% in both studies, as compared to a health-focused label. Another trick can be to highlight the dish’s origin: in a real-world test, changing a Panera item from “Low Fat Vegetarian Black Bean Soup” to “Cuban Black Bean Soup” resulted in a 13% sales bump.
According to one experiment, adding the environmental impact next to each food item can get some people, especially women, to choose the more sustainable veg options. This might be an ideal strategy for climate-conscious conferences and similar venues.
One important caveat: advocates we spoke to who are working in the Global South, where the word “vegan” is not as mainstream, argue that using the word “vegan” allows the movement to become more salient and legitimate, outweighing potential disadvantages. Their anecdotal observations are a good reminder that most studies on using the words “vegan” vs. other terms like “plant-based” are conducted in the U.S. and Europe, so it’s certainly possible their findings don’t translate to other regions.
In regions with a higher understanding of veganism, that word just doesn’t seem to cut it. One thesis found that modified animal meat terms (like chick’n or bakon) made the foods seem more typical but both terms like “plant-based chicken” and “chick’n” increased willingness to buy over veggie-based terms like “veggie chicken.”
However, smaller tweaks to menu design may not be noticed by diners. In one restaurant study, only around 36% of diners noticed a message indicating the growing popularity of vegetarian dishes in the top-right corner of a menu. So be wary of having the nudges be too tiny.
Reach Out to Men And Other Meat-lovers, If Necessary
It’s well-established that men are less likely to be vegan and take other pro-animal actions compared to women and non-binary folks, but men are also more likely to opt out of default veg options and less likely to be swayed by plant-based nudges. This isn’t a dealbreaker — nudges aren’t intended to get meat consumption down to zero by themselves. However, if your audience is disproportionately men or another group prone to eating meat, you might need to add some extra framing to ensure success.
Men don’t like the words “vegan” or “plant-based”, but might be more accepting of words like “direct protein” or “high protein.” However, while another study showed that masculine labels (like “meaty” or “beast”) made men believe the food was more masculine, it didn’t make them more likely to view the food more favorably. So, the evidence is mixed on macho menus, but the good news is that masculine words didn’t backfire — it may be worth a shot.
There are other strategies to entice men and veg-avoiders. One option may be to highlight the veg dish as the “chef’s selection,” which was successful in one study to convince veg-avoiders to eat the veg dish. Other studies have found that increasing the vegan ratios increases total veg orders for all demographics, meat lovers included.
Add Reflection To The Nudge
Nudges are great, but they can work even better when paired with education, reflection, or a diet pledge. In one field study, university students were nudged via food labels, and then sent emails asking them to reflect on the nudge or the climate impact of their diet. Those who were given the nudges and the reflection ordered the least amount of meat. Another online study found that asking participants to commit to a diet pledge before a nudge made them significantly more likely to order a plant-based option.
This may work because “bimodal” strategies — strategies in which the menus and food halls were changed in addition to advocating promotional messages — were found to be the most effective at meat reduction in university food halls according to a meta-analysis.
Depending on the context, try integrating automated reflection emails, posters, or questionnaires into an existing campaign — this extra reflection may reduce meat consumption even further.
Make The Food Appealing, Diverse, And Inclusive
It will come as a shock to no one that people tend to choose food they like! Make sure to put thought into the default veg option. If it’s not appealing, the success rate falls quickly. Most of the studies we looked at were careful to only test appetizing plant-based options, so all the benefits described above are contingent on tasty food.
Taste is just one consideration, however. A big appeal of PBD programs is that plant-based options are more inclusive — in a world where about 68% of people can’t digest cow’s milk, many people also have religious, ethical, or health-related reasons for avoiding eating animal products. PBDs offer a more inclusive alternative, and advocates can leverage this appeal. Making veg dishes allergy-friendly may help as well, if it’s possible not to put nuts or soy in every dish.
Be Creative!
Nudges are a broad category, and some can include more out-of-the-box ways of changing the choice architecture. One study found that having more decorative plants and an herbal odor in the dining hall reduced university students’ meat consumption by 42%. This works due to priming — basically the situational cues that may unconsciously drive behavior. Of course, advocates may not always have control over a physical space, but it shows some potential as an effective way to nudge people in the right direction.
A student thesis found that showing people a cartoon video of a character physically looking at the vegan options made flexitarians more likely to choose them — the cartoon even gave a thumbs’ up when the person chose a vegan option. This nudge made people more likely to actually view the vegan option, which increased the odds that they would buy it. Again, this might not work in all situations, but if the occasion arises, give it a try.
Sequence Your Menus Effectively
Just like with Star Wars marathons and Spotify playlists, order is everything. In particular, dishes placed at the top or bottom of a menu can increase their popularity by up to two times and may reduce the amount of meat sold by up to 11% when that first option is veg-based.
The order of a buffet line matters as well. One study found that fruits and veggies, when separated and served at the front of a buffet, were more likely to be picked up. Another study found that foods placed on the edges of a buffet (making them easier to access) were more likely to be chosen by consumers.
All in all, veg items need to be first, last, or somehow prominently displayed in order to be chosen in higher amounts.
The Bottom Line
Nudges are an increasingly popular and effective intervention to reduce the amount of meat sold in a food service. However, there are some things we don’t know, like if people eat more or less meat after encountering a plant-based default (either later in the day or later in their life). We also need more research on spillover — in which people avoid the PBD station, cafeteria, or restaurants entirely — as this might reduce the intervention’s impact. We also don’t know to what extent PBDs can influence a broader cultural change.
Despite these limitations, we’re confident that, in the short-term, plant-based defaults are quite effective at reducing meat consumption within a university or institution. Their popularity and scalability make them promising interventions.
If you are an advocate seeking to bring plant-based defaults to your community or into your outreach work, you can contact Better Food Foundation at [email protected] for resources and support. University students can also sign up for BFF’s immersive student ambassador program. If you are an internal ally (meaning you have a professional relationship with a key decision maker) in a workplace, hospital, or other venue involving food service and are interested in helping implement a plant-based default, Greener By Default invites you to reach out at [email protected].
If you have questions about the research, we encourage you to contact the Faunalytics team or visit our Office Hours.
Faunalytics is deeply appreciative of the thoughtful contributions from Hannah Hughes (Better Food Foundation), Ignacia Uribe (Fundación Veg), Laura Lee Cascada (Better Food Foundation), Kenzie Bushman (Better Food Foundation), Stef Lynch (Better Food Foundation), and Ilana Braverman (Greener by Default).
Sources / Read More
Plant-Based Defaults
- Using the Default Nudge to Increase Plant-based Meal Consumption on College Campuses
- Plant-based default nudges effectively increase the sustainability of catered meals on college campuses: Three randomized controlled trials
- Can Green Defaults Reduce Meat Consumption?
- Serving Up Plants By Default
- Can you default to vegan? Plant-based defaults to change dining practices on college campuses
- Nudging healthy and sustainable food choices: three randomized controlled field experiments using a vegetarian lunch-default as a normative signal
- Veg on the menu? Differences in menu design interventions to increase vegetarian food choice between meat-reducers and non-reducer
- A reversal of defaults: Implementing a menu-based default nudge to promote out-of-home consumer adoption of plant-based meat alternatives
- Changing the default meal option at university events to reduce harmful environmental impacts: Six randomized controlled trials
Menu Design
Plant-Based Food Labels
- Vegan labeling for what is already vegan: Product perceptions and consumption intentions
- Vegetarian, vegan, or plant-based? Comparing how different labels influence consumer evaluations of plant-based foods
- Vegan burger, no thanks! Juicy American burger, yes please! The effect of restaurant meal names on affective appeal
- A “vegetarian curry stew” or just a “curry stew”? – The effect of neutral labeling of vegetarian dishes on food choice among meat-reducers and non-reducers
- Smart food policy for healthy food labeling: Leading with taste, not healthiness, to shift consumption and enjoyment of healthy foods
- Don’t say “vegan” or “plant-based”: Food without meat and dairy is more likely to be chosen when labeled as “healthy” and “sustainable”
- What To Call Plant-Based Meat Alternatives: A Labeling Study
- Simple Eco-Labels to Nudge Customers Toward the Most Environmentally Friendly Warm Dishes: An Empirical Study in a Cafeteria Setting
- Increasing Vegetable Intake by Emphasizing Tasty and Enjoyable Attributes: A Randomized Controlled Multisite Intervention for Taste-Focused Labeling
- “I’ll try the veggie burger”: Increasing purchases of sustainable foods with information about sustainability and taste
- It’s All in a Name: How to Boost the Sales of Plant-Based Menu Items*
- Descriptive language on label nudging to promote plant-based diet
Menu Structure
- Meat on the menu? How the menu structure can stimulate vegetarian choices in restaurants
- (Not) Eating for the environment: The impact of restaurant menu design on vegetarian food choice
- Don’t Put Vegetables in the Corner: Q&A with Behavioral Science Researcher Linda Bacon*
- To veg or not to veg? The impact of framing on vegetarian food choice
- Developing a Scalable Dynamic Norm Menu-Based Intervention to Reduce Meat Consumption
- Nudging plant-based meals through the menu
Menu Order
- Nudge to nobesity II: Menu positions influence food orders
- Nudge the Lunch: A Field Experiment Testing Menu-Primacy Effects on Lunch Choices
- Increasing fruit and vegetable intake among male university students in an ad libitum buffet setting: A choice architectural nudge intervention
Ratios
- Menu design approaches to promote sustainable vegetarian food choices when dining out
- How meat-free meal selection varies with menu options: an exploration
- Impact of increasing vegetarian availability on meal selection and sales in cafeterias
- Impact of increasing the relative availability of meat-free options on food selection: two natural field experiments and an online randomised trial
- Nudging greater vegetable intake and less food waste: A field experiment
*evidence-based blogs or resources, not original research
Nudge Theory & Norms
Nudge Overviews
- Using Nudges To Make Change For Animals*
- A systematic review: the effect of nudging towards a plant-based diet
- Motivating Sustainable Food Choices: The Role of Nudges, Value Orientation, and Information Provision
- Do The Effects of Nudges Persist? Theory and Evidence from 38 Natural Field Experiments
Social Norms
- Leveraging Social Norms For Animal Advocacy*
- Ethics, Social Norms, And Eating Animals*
- The Effect Of Social Norms On Meat Consumption*
Messaging and Framing
- “Reduce” Or “Go Veg”? Effects On Meal Choice
- Changing Men’s Perceptions Of Veganism Through Framing
- It Takes More Than A Nudge To Reduce Meat Consumption
- Bringing Back Former Vegans And Vegetarians: An Obstacle Analysis
- Choice Architecture in Food Services
*evidence-based blogs or resources, not original research
Other Nudges
Estimating Benefits
Adding Reflection to Nudge
- Sustainable dietary choices improved by reflection before a nudge in an online experiment
- Pledging after nudging improves uptake of plant-based diets: a field experiment in a German university cafeteria
Visibility
Supermarket Nudges
- How to reduce agri-environmental impacts on ecosystem services: the role of nudging techniques to increase purchase of plant-based meat substitutes
- Nudging at the checkout counter – A longitudinal study of the effect of a food repositioning nudge on healthy food choice
- Nudging plant-based alternatives to meat and dairy in a real-life online supermarket: A randomized controlled trial
Miscellaneous
- Comparison of three nudge interventions (priming, default option, and perceived variety) to promote vegetable consumption in a self-service buffet setting
- Stimulating Vegan Food Choices With the Affordance Nudge: A One-Size Fits All Solution?
- Changes in children’s meal orders following healthy menu modifications at a regional US restaurant chain
- Food Choice Architecture: An Intervention in a Secondary School and its Impact on Students’ Plant-based Food Choices
- The Rise of Veg, the Fall of Meat: A Restaurant Case Study
- Increasing vegetable consumption out-of-home: VeggiEAT and Veg+projects
- Forced Choice Restriction in Promoting Sustainable Food Consumption: Intended and Unintended Effects of the Mandatory Vegetarian Day in Helsinki Schools
- Default options, incentives and food choices: evidence from elementary-school children
- Effect of a default portion-size reduction on meat consumption and diner satisfaction: Controlled experiments in Stanford University dining halls
- Lessons From University Meat Reduction Initiatives
*evidence-based blogs or resources, not original research
