Add a Legume to Your Cart

In the first task, specifically designed for the present study, participants are asked to complete a simulated online grocery shopping for the following week. The task is structured to closely resemble a real shopping experience: each item can be added to the virtual cart in a potentially unlimited number of units, with higher values indicating larger quantities purchased and a value of zero indicating that the item was not selected.

The primary outcome will consist of the total number of legume-based items selected, subsequently converted into servings. This conversion process will be carried out by the nutrition research team.

Participants were asked to express their opinions about legumes using six different bipolar scales, introduced with the following instruction:

"Now think about legumes (e.g., chickpeas, peas, beans, lentils, broad beans). Which adjectives do you consider most appropriate to describe them? Please respond to each pair of adjectives without overthinking your answer."

The bipolar adjective pairs were as follows: negative-positive; bland-tasty; isolating-convivial; unsatisfying-satiating; difficult-easy; loser-winner.

Responses were recorded on 7-point scales ranging from 1 (indicating the negative pole of each adjective pair) to 7 (indicating the positive pole of each adjective pair).

The Swipe Approach-Avoidance Task (SwipeAAT) is a smartphone-based version of the Approach-Avoidance Task, in which participants interact with visual stimuli according to specific instructions. Stimuli must either be "approached" (by swiping upward) or "avoided" (by swiping downward) depending on the instructions provided. Reaction times recorded during task performance are analyzed to infer spontaneous behavioral tendencies of approach or avoidance toward the presented stimuli.

To assess spontaneous approach and avoidance tendencies toward legumes and meat, two scores were computed for each participant:

Legume SwipeAAT score, calculated as the difference between the mean of all valid latencies (see Data Exclusion) for the "Avoid legumes" trials and the "Approach legumes" trials.

Meat SwipeAAT score, calculated as the difference between the mean of all valid latencies (see Data Exclusion) for the "Avoid meat" trials and the "Approach meat" trials.

Participants were asked to report their future intention to increase their weekly consumption of legumes using a single-item measure ("Do you intend to increase your consumption of legumes in the near future?"). Responses were provided on a 5-point scale ranging from 1 ("absolutely not") to 5 ("absolutely yes").

In addition to legumes, purchases made during the online grocery shopping simulation task will also be analyzed for other categories of interest, including meat, fruit and vegetables, processed foods, and related product categories.