An interventional study of Guideline Daily Amounts and Multiple Traffic Light in Food Labeling, sponsored by Instituto Nacional de Salud Publica, Mexico. Completed at 8 sites in Mexico. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2020-03-17.
Sponsored by Instituto Nacional de Salud Publica, Mexico · Not applicable, Interventional, and Prevention
The effect of three front of pack (FOP) labeling schemes (Mexican Guideline Daily Amounts (GDA), Ecuador's Multiple Traffic Light (MTL) and Chilean Warning Labels (WL) in red) on purchasing intentions was evaluated using a randomized experiment of an online shopping simulation. The study employed an online grocery store developed for this purpose to simulate a shopping situation.
Nutrition labels may modify purchasing behavior. Different labels may influence consumer purchasing behaviors in different ways.
In general, for nutrition labels to have any effect on purchasing decisions, consumers must first be exposed to them and perceive the displayed information on the labels. Then, the effect will be mediated by consumer understanding. Based on this understanding, consumers may use the label to make inferences about the nutritional quality or healthiness of the product, which, together with other information (e.g. trust or liking of the label or taste of the product) may affect the evaluation of the product and eventually the purchase decision of the product.
GDA provide numeric information on the content of key nutrients in the food product without interpreting the information.
MTL and WL are nutrient-specific labels providing an interpretation of the nutritional content of specific nutrients in the product. The MTL uses traffic light colors to indicate the high (red) or low (green) content of key nutrients, whereas the WL are only included in a product when the content of each key ingredient is above specific criteria.
Trained undergraduate student research assistants from eight universities across the country recruited the study participants. Research assistants were trained on how to approach and recruit participants and obtain informed consent. They were instructed to recruit 20 or more participants each. Recruitment took place in public spaces previously selected by convenience by the research team, based on their use by low- and middle-income groups in Mexico (i.e., public schools, public squares, public health centers, as well as supermarket chains and shopping centers located in low-income neighborhoods). Potential participants were approached by research assistants, who explained study objectives and invited them to be part of the study. Then, individuals were screened for eligibility using a 3-item screener. To access this screener, research assistants used a tablet or laptop with internet-access, to access a unique web address where our web-based tool was hosted. Research assistants were automatically informed by the web-based tool about the eligibility of the participant. Informed consent was obtained from all eligible participants using an automated computer-based form. Then, the tablet or laptop was handed to participants, who completed a self-administered online demographic and health survey, and then accessed the online shopping site to simulate a shopping situation. Participants completed the shopping task on the same day at the public place where they were recruited.
After allocation, participants viewed a video explaining how to correctly interpret the assigned label. Each participant was asked to shop freely, to better mimic real-world grocery shopping conditions. Research assistants instructed participants as follows: "take into account the assigned label and choose your preferred products". Participants were assigned an initial budget to do their shopping, although they did not pay actual money for their groceries. This budget corresponded to their weekly expenditure in groceries reported in the demographic survey, from 500-5000 Mexican pesos ($28-280 USD), in multiples of 500. No specific instructions were given related to the number or total cost of food products purchased.
FOP nutrition labels were affixed on the food items of the virtual supermarket. The store displayed the name, price and the front of the pack image of 60 food products from 5 food groups (ready-made foods, dairy products, non-dairy beverages, salty snacks, and breakfast cereals). Products were shown on traditional shopping shelves. Participants could zoom in to look more closely at the products and their prices, and could click on the product to access a new pop-up window. This new window displayed product information (i.e., name and brand), a larger image of the front of the product packaging, and an area where they could select the amount or number of products they wanted to put in their shopping cart. The pop-up window was the only way in which participants could select the food products to "purchase". Participants could also zoom in further on this pop-up to look more closely at the package and the nutritional label.
After completing their shopping, participants revised their shopping cart and "purchased" their products. A brief feedback on the nutritional quality of the products in their shopping cart was provided as a retribution for their time.
Instituto Nacional de Salud Publica, Mexico is the lead sponsor of 30 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Guideline Daily Amounts (GDA) is a purely numerical and reductive labeling system, indicates the grams and percentages (according to the guideline-based daily intakes) per portion of kilocalories, saturated fats, other fats, sugars, and sodium, with no specific judgement, opinion or recommendation.
Behavioral: Guideline Daily Amounts · Behavioral: Video
Multiple traffic light labels, an interpretive nutrient-specific FOP label, use the typical traffic light colors (green, yellow/amber, red) and text descriptors to indicate the high, medium, or low content of total fat, sugar and salt.
Behavioral: Multiple Traffic Light · Behavioral: Video
Warning Labels (WL), another nutrient-specific interpretive FOP labelling scheme, include 'high in' symbols for products that exceed limits of energy, sodium, sugar and saturated fat.
Behavioral: Warning Labels · Behavioral: Video
All food items displayed the corresponding GDA label in the lower left corner of the front of the package.
All food items displayed the corresponding MTL label in the lower left corner of the front of the package.
Food products were labeled with "High in" labels In the lower left corner of the front of the package. In total, 37 of the 60 food products in the shopping site did not display a WL.
Participants viewed a short (less than 1 min) video explaining how to interpret the label.
Mean nutritional quality of the shopping cart
The Nutrient Profiling Scoring Criterion model was used as the main measure to evaluate the nutritional quality of the shopping cart.
Time frame: On the date of randomization
Mean nutritional quality of the shopping cart (negative nutrients)
The Nutrient Profiling Scoring Criterion baseline score, considering only negative nutrients, was used to explore a nutritional quality measure consistent with the key nutrients evaluated.
Time frame: On the date of randomization
Mean protein content
The mean protein content per 100g or 100 mL of the purchased items was calculated by dividing the total protein content in the shopping cart by the number of products purchased
Time frame: On the date of randomization, after completion of the online shopping simulation
Mean fiber content
The mean fiber content per 100g or 100 mL of the purchased items was calculated by dividing the total fiber content in the shopping cart by the number of products purchased
Time frame: On the date of randomization, after completion of the online shopping simulation
Mean sodium content
The mean sodium content per 100g or 100 mL of the purchased items was calculated by dividing the total sodium content in the shopping cart by the number of products purchased
Time frame: On the date of randomization, after completion of the online shopping simulation
Mean sugar content
The mean sugar content per 100g or 100 mL of the purchased items was calculated by dividing the total sugar content in the shopping cart by the number of products purchased
Time frame: On the date of randomization, after completion of the online shopping simulation
Mean saturated fat content
The mean saturated fat content per 100g or 100 mL of the purchased items was calculated by dividing the total saturated fat content in the shopping cart by the number of products purchased.
Time frame: On the date of randomization, after completion of the online shopping simulation
Mean energy content
The mean energy content per 100g or 100 mL of the purchased items was calculated by dividing the total energy content in the shopping cart by the number of products purchased
Time frame: On the date of randomization, after completion of the online shopping simulation
Mean fat content
The mean fat content per 100g or 100 mL of the purchased items was calculated by dividing the total fat content in the shopping cart by the number of products purchased
Time frame: On the date of randomization, after completion of the online shopping simulation
Time to first product selection (minutes)
Calculated as the time required to "buy" a product after entering the online grocery store.
Time frame: On the date of randomization, during the online shopping simulation
Time spent looking at a product before deciding to buy it (seconds)
Estimated as the time between observing the food product on the pop-up window and clicking on the "add to shopping cart" button
Time frame: On the date of randomization, during the online shopping simulation
Time spent looking at a product before deciding not to buy it (seconds)
Estimated as the time between observing the food product on the pop-up window and going back to the shopping shelf
Time frame: On the date of randomization, during the online shopping simulation
Total time spent shopping (minutes)
Calculated as the time spent shopping, between entering and exiting the online grocery store.
Time frame: On the date of randomization, after completion of the online shopping simulation
Documents are hosted by the registry — open the source record to download them.
Plan to share: Yes — De-identified individual participant data will be made available upon request.
Supporting information: Study protocol, Sap, Icf
This study is completed, as verified in Mar 2020. You cannot join it, but the record below documents what was studied.
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Instituto Nacional de Salud Publica, Mexico