Animal-sourced food production is a significant contributor to greenhouse gas (GHG) emissions and climate change. Nearly 80% of the GHG emissions from global agriculture is caused by animal farming alone. The current rate of consumption of animal-sourced foods is unsustainable. In order to reduce emissions, it’s crucial that plant-based alternatives are adopted on a wider scale.

To encourage this shift, research has sought to identify ways to motivate consumers to choose plant-based products. However, so far, those choices have mostly been investigated in the context of restaurants or supermarkets, not online. Online grocery shopping has been rising rapidly in recent years, with over 45% of shoppers regularly buying groceries online. As online grocery shopping continues to grow in popularity, it’s important to understand how the online storefront may affect purchasing decisions when it comes to plant-based foods.

This study aimed to determine whether carbon footprint labels and product categorization influenced the selection of plant-based foods in an online shopping environment.

Researchers recruited a sample of 2,359 adults representative of the U.S. population for gender, race, age, income, and geographic region. Participants shopped in a simulated online grocery store (the Open Science Online Grocery (OSOG) platform) containing over 11,000 real-world products. Plant-based foods accounted for around 40% of the total products available in the store, and cost an average of $3.65 compared to an average of $3.13 for their animal-sourced counterparts.

Grocery items were divided into four categories: meat, milk, cheese, and yogurt. There were both animal-sourced and plant-based options in each category. Given a budget of $20, the participants were asked to buy products in all four categories.

To measure the impact of two different interventions on their selection of plant-based products, the participants were randomly assigned to one of four groups:

1. Control: All products were presented as is with no special labels or categories.
2. Carbon footprint label: All products included color-coded labels specifying GHG emission values.
3. Categorization: The plant-based products were categorized as “sustainable foods.”
4. Combined: All products had carbon footprint labels and the plant-based products were also categorized as “sustainable foods.”

When the study concluded, participants had checked out 8,320 grocery items in their virtual carts, of which 5,200 were plant-based. Close to 16% of the participants didn’t select any plant-based products.

Analysis indicated that, compared to the control, both carbon footprint labeling and categorization increased plant-based food selection by 37% and 25%, respectively. When carbon footprint labels were combined with categorization, participants increased their selection of sustainable products by 32% compared to the control group. However, these results were not even across product categories. Categorization didn’t affect selection in the meat category. And while the interventions increased the selection of plant-based meat, milk, and cheese, they had no impact on the yogurt category.

The authors proposed three reasons for the inconsistent effects across product categories. These included:

• The varied proportion of plant-based foods: When more plant-based options were available in a given category, more plant-based products were selected.

• The uneven differences in GHG emission values: Some GHG emission differences between plant-based and animal-sourced products were huge, while others were smaller.

• Consumer acceptance of the product: Taste, preferences, and familiarity can all influence product choice. Highlighting the importance of taste, for instance, the authors pointed to previous research demonstrating that consumers simply don’t like plant-based yogurt.

In addition to these inconsistencies, the authors pointed out two limitations. While the OSOG includes a large selection of real-world products, consumers may have access to fewer or different items in real life depending on which online retailer they use. Also, participants didn’t use their own money or actually receive the foods they ordered. Given these limitations, we can’t be certain how closely the experiment replicates shoppers’ real-world choices.

With the popularity of online grocery shopping and the effectiveness of the relatively simple nudges explored here, the results of this study are quite encouraging for animal advocates. However, there are a number of factors to consider for these types of interventions to be effective in the real world. Consumers may be influenced by certain adjustments to their online purchasing environment, but only if they’re already comfortable with the alternatives. For example, consumers were less likely to choose plant-based yogurt, regardless of nudges, likely because it’s not as familiar or appealing as other plant-based alternatives such as milk. Feasibility is also a consideration. While this study indicates that carbon footprint labeling would be most effective, it’s more difficult to execute than simply categorizing products as “sustainable.” Though online grocery shopping makes interventions easier to implement and scale up compared to a traditional retail store, the underlying challenge will be to continue to increase both the availability of and consumer confidence in quality plant-based foods.