The objective of this research was to determine if adding a plate graphic depicting the components of the Eat Lancet Planetary Health diet (Figure 1) to food labels in Stanford University dining halls would lead to dining hall patrons making dietary decisions that better resemble the Planetary Health diet in comparison to a no signage control group. The study hypothesis was that presenting students with a plate graphic featuring the healthy reference diet would decrease objective measures of the amount of meat taken and therefore the environmental impact of student meals.

Research was conducted into the everyday experience of dining hall patrons. All participants were patrons of Florence Moore Dining Hall on the Stanford University campus where all data was collected. Patrons were largely undergraduate students.This investigation was designed as a crossover randomized control trial with two phases: (1) a Planetary Health Plate (PHP) intervention phase where signage promoting the planetary health diet was posted and (2) a control phase with signage as usual. Stanford Dining serves food on a four-week menu cycle; this pattern results in several academic weeks that are intended to be identical in food served. To standardize the conditions and limit potential confounding, the experimental and control phases were each randomized to one of the weeks throughout the quarter when the same, "week two" menu was to be served. Data was collected for the control phase during week two of the academic winter quarter and data with the PHP posted was collected during week six of the academic winter quarter.

On each data collection day, two different types of meat dishes were provided by the Dining Hall and there were two stations with each type. Research assistants weighed each serving tray of meat as it came from the kitchen and again before returning the used serving tray to the kitchen, to determine the total amount of meat taken from the tray. Tally counters were used to count the number of patrons who took meat from the tray. Qualitative notes about patron behavior and possible deviations from data collection protocol were recorded on data collection sheets. After each dinner collection period, Stanford Dining provided the total number of people who entered the dining hall during the designated dinner periods on each of the data collection days. This was based on the number of unique identification card swipes into the dining hall during dinner times.

Comparison was made between 1) dietary behavior without signage, and 2) behavior while exposed to PHP during four equivalent dinner meals.

Inclusion criteria:

• Patrons of Florence Moore Dining Hall at Stanford.

Exclusion criteria:

• None