The effect of food packaging color on calorie estimation in virtual reality

Abstract

Despite extensive research on food labeling, little is known about how color cues influence calorie estimation and food choices in immersive environments. This study explores the impact of packaging color (red vs. green) on caloric estimation and consumer behavior in a virtual reality shopping context. Two experimental studies (N = 279) were conducted using a VR shopping environment to examine the effects of packaging color on calorie estimation and product selection. A between-subjects design was used, manipulating color variations (Red vs. Green) and health perception (Related vs. Unrelated groups). Study 1 (N = 159, aged 18–32) and Study 2 (N = 120, aged 17–28) recruited participants via social media. The study investigates how packaging color influences caloric estimation and the mediating role of perceived healthiness in shaping consumer choices. Independent sample t-tests and ANOVA were conducted, with bootstrap methods applied to test for mediating effects. Red packaging increases calorie estimations and reduces product selection, while green enhances perceived healthiness and purchase intent. The mediating role of perceived healthiness is significant, and neutralizing the color-health association weakens these effects, leading to increased food selection. Adjusting packaging color could serve as a behavioral nudge for healthier consumer choices, providing strategic insights for food marketing and public health policies. These findings highlight the potential for regulatory measures and industry strategies to leverage color cues in promoting healthier consumption behaviors.

Supplementary Information

The online version contains supplementary material available at 10.1038/s41598-025-16468-6.

Introduction

Obesity is a complex disease that not only affects an individual’s appearance but also has multifaceted negative impacts on physical health, including cardiovascular diseases, type 2 diabetes, hypertension, fatty liver disease, and certain types of cancer¹. Additionally, obesity contributes to psychological distress, increasing the risk of depression and anxiety, and imposes a significant economic burden on public health systems^2,3. Given the rising prevalence of obesity, understanding how consumers estimate food calories and make dietary choices is essential for both public health and marketing strategies. Previous research has strongly linked obesity with the underestimation of food calories, highlighting the need for interventions that help consumers make more informed choices^4–6.

Food choices are influenced by various factors, including economic conditions, sociocultural influences, psychological aspects, marketing strategies, and food packaging design^7–9. Among these, food packaging color plays a crucial role in shaping consumer perceptions and decision-making. Colors can act as implicit cues that influence caloric estimations, thereby affecting consumers’ food selections and dietary behaviors¹⁰. As a key element of sensory marketing, packaging color has the potential to nudge consumers toward healthier choices, making it a valuable tool for both businesses and policymakers.

Despite extensive research on food packaging and consumer behavior, there remains a significant research gap regarding how color influences calorie estimation and the mediating role of perceived healthiness in this relationship. Furthermore, most existing studies rely on self-reported surveys or controlled laboratory experiments, which may lack ecological validity. This study uses virtual reality technology to investigate how food packaging color (red vs. green) influences consumers’ calorie estimations and whether perceived healthiness mediates this effect. By uncovering these mechanisms, this research provides insights that are relevant not only to public health interventions but also to food industry marketing strategies and regulatory policies. Specifically, these findings can inform front-of-pack labeling regulations and guide food manufacturers in designing health-oriented packaging that encourages better consumer choices^11,12. Given the increasing emphasis on behavioral nudges in public policy, understanding the impact of color-coded cues on food perception can help develop more effective marketing and regulatory frameworks, ultimately contributing to obesity prevention and healthier consumer behavior.

Color, caloric estimation, and perceived healthiness

Color is one of the most immediate and influential visual cues in food packaging, shaping consumer perceptions and decision-making processes. Previous research has highlighted the significant impact of front-of-pack (FOP) visual cues on consumer food choices and eating behaviors, emphasizing the role of packaging color as a critical element in shaping dietary decisions¹³. Consumers frequently rely on packaging color to infer the healthiness and caloric content of food rather than consulting detailed nutritional labels^5,14,15. However, the specific mechanisms by which color affects food health perception and caloric estimation remain unclear, particularly regarding the mediating role of perceived healthiness in this relationship.

Food packaging color plays a crucial role in shaping consumer perceptions of healthiness. Research has shown that color-coded packaging influences consumer expectations about food attributes, often more strongly than textual nutritional information¹⁶. Green is typically associated with health, natural ingredients, and lower calories, whereas red is often linked to high-calorie, indulgent, and less healthy foods^17,18. These associations arise not only from everyday experiences but also from strategic marketing practices. Many health-oriented products use green packaging to emphasize their nutritional benefits, while high-calorie snacks or fast foods often employ red to attract attention and stimulate impulse purchases^19,20. Moreover, color influences sensory expectations, with red enhancing perceptions of richness and indulgence, whereas green can make food seem healthier but potentially less flavorful²¹. Recent research has expanded from examining singular color effects to investigating the interactions between color and other visual cues, such as shape and labeling²². Recent research by Hallez et al. (2023) further supports the significant role of packaging color in shaping consumer perceptions of healthiness, sustainability, and taste among young consumers. Their study demonstrates that color, in interaction with packaging claims, influences product evaluations, with findings closely aligning with the current research on color-driven health perceptions. This highlights the importance of considering interactive effects between color and other visual or textual cues in food packaging design, an area warranting further exploration in the context of calorie estimation²³. For example, Grunert & Wills (2007) found that consumers prefer simplified front-of-pack labeling formats but differ in their reliance on color-based health cues depending on the product category and context²⁴. However, the precise mechanisms by which color influences food health perception require further empirical validation.

Studies suggest that consumer perceptions of a food product’s healthiness significantly influence their caloric judgments²⁵. Prior research indicates that consumers tend to overestimate the caloric content of foods they perceive as unhealthy while underestimating those they deem healthy²⁵. This phenomenon has been observed in various contexts; for example, when consumers compare two identical yogurt products labeled as “low-fat” and “full-fat,” they consistently judge the full-fat yogurt as having higher calories, despite both products containing the same caloric content²⁶. Similarly, fast food consumers—especially those frequenting health-branded chains such as Subway—tend to underestimate the caloric content of meals, leading to higher caloric intake²⁷. In one study, participants were asked to evaluate the healthiness and caloric content of eight different foods. The results showed that foods perceived as healthy or beneficial for weight loss were typically underestimated in caloric content, whereas foods perceived as unhealthy or detrimental to weight loss were overestimated¹⁷. Furthermore, the health-oriented branding of a restaurant can lead consumers to underestimate the caloric content of its meals, resulting in increased caloric intake¹⁴. These findings indicate that consumers do not estimate calorie content directly based on the food itself but rather indirectly through their judgments of healthiness. Thus, food packaging color may first influence health perception, which in turn affects caloric estimation^19,20. While perceived healthiness has been widely studied in consumer decision-making, its specific mediating role in the color–caloric estimation relationship remains underexplored.

Overall, food packaging color may influence caloric estimation by first shaping consumers’ perceptions of healthiness. However, most existing research has focused on color’s impact on food choice and consumption behavior, with limited direct investigation into how color affects caloric estimation²². Additionally, prior studies have relied primarily on self-reported surveys or controlled laboratory experiments, which may lack ecological validity. With the development of Virtual Reality (VR) technology, this research integrates VR to further enrich and develop its application in consumer behavior studies. Compared to traditional research methodologies, VR technology offers low costs, reusability of experimental scenarios, and immersive experiences that more accurately replicate real-world environments²⁸, thereby holding significant advantages in consumer research. Therefore, this experiment leverages VR technology to perform experimental manipulations, aiming to explore the underlying mechanisms more profoundly.

Theoretical framework: association theory and embodied cognition theory

Sensory marketing research frequently utilizes Association Theory and Embodied Cognition Theory to explain how sensory cues influence consumer perceptions and behaviors. These theories provide a foundation for understanding how color cues (red vs. green) affect consumers’ calorie estimations through their perceptions of healthiness.

Association Theory posits that repeated co-occurrences of stimuli lead to learned associations, allowing consumers to anticipate one event based on the presence of another²⁹. In food packaging, red and green are commonly used in health-related messaging, shaping consumer expectations. Red is often associated with cautionary signals, energy, and intensity, while green is frequently linked to health, natural ingredients, and lower-calorie options. These learned associations influence consumer judgments, leading to expectations that green-packaged foods are healthier and lower in calories, whereas red-packaged foods may be perceived as less healthy and higher in calories. This heuristic processing may guide consumer decision-making, particularly in contexts where detailed nutritional information is not immediately considered.

Embodied Cognition Theory, in contrast, suggests that cognitive processes are deeply rooted in bodily interactions with the environment, meaning that sensory experiences—such as visual exposure to color—can directly shape cognitive evaluations and perceptions. Research has demonstrated that bodily perceptions significantly impact consumer experiences; for instance, tactile sensations influence service perception, with soft textures enhancing tolerance for service failures³⁰, while rough textures evoke empathy and generosity³¹. Similarly, product shape affects size perception, as consumers tend to perceive round pizzas as smaller than square pizzas of the same surface area³². In the context of food perception, color can elicit immediate cognitive and affective responses, influencing how consumers assess healthiness and caloric content. Red may enhance perceptions of higher energy content, whereas green may reinforce associations with health and lower caloric density.

By integrating Association Theory and Embodied Cognition Theory, this study examines how packaging color influences consumers’ calorie estimations through their perceptions of healthiness, providing insight into the cognitive mechanisms underlying food-related judgments.

Research objectives

This study aims to investigate how food packaging color (red vs. green) influences consumers’ calorie estimations and whether perceived healthiness mediates this effect. While previous research has demonstrated that color cues shape consumer perceptions, the underlying cognitive mechanisms—particularly the mediating role of perceived healthiness—remain underexplored. Drawing on Association Theory and Embodied Cognition Theory, this research seeks to clarify how learned associations (e.g., red with unhealthiness and green with health) and direct sensory experiences influence food-related judgments.

Specifically, this study examines whether red packaging leads to higher calorie estimations and green packaging leads to lower ones, particularly in the context of unhealthy foods. Since consumers often rely on heuristic cues, color may serve as a visual shortcut for evaluating a product’s healthiness, subsequently influencing calorie estimation. However, if the association between color and healthiness is disrupted—such as through an experimental manipulation where color is framed as unrelated to health—the effect of color on calorie estimation should diminish. Additionally, this research explores whether altering the color-health association affects consumers’ food choices, potentially leading to an increase in food selection when color no longer serves as a heuristic signal for health.

To address these research objectives, the following hypotheses are proposed:

H1: For unhealthy foods, red packaging will increase consumer calorie estimations compared to green packaging.

H2: Perceived healthiness mediates the effect of packaging color on calorie estimation of unhealthy foods.

H3: For unhealthy foods, the association of red with unhealthiness will lead to higher calorie estimations of foods in red packaging. After manipulating “color unrelated to health,” the impact of color on calorie estimation will disappear in the manipulated group.

H4: Compared to the control group, the number of food choices will increase in the manipulated group where “color is unrelated to health.”

By testing these hypotheses, this study seeks to provide both theoretical contributions to sensory marketing and practical implications for food packaging design and public health communication. Understanding how color influences calorie estimation through perceived healthiness can inform strategies for promoting healthier eating behaviors and improving consumer awareness of nutritional content.

Study 1: the impact of food packaging color on calorie Estimation

Study 1 employs a single-factor between-subjects design, with the independent variable being packaging color, divided into two levels: red and green. The dependent variable is the numerical estimation of calories, and the mediating variable is the perceived level of healthiness.

Experimental objectives and hypotheses

The purpose of Study 1 is to explore the impact of food packaging color on calorie estimation and to examine the mediating mechanism of perceived healthiness. The following hypotheses are proposed for this experiment:

H1: For unhealthy foods, red packaging will increase calorie estimations compared to green packaging.

H2: Perceived healthiness mediates the effect of packaging color on calorie estimation for unhealthy foods.

Participants

Participants were recruited through the distribution of a survey link on social media platforms using Questionnaire Star. A total of 159 respondents completed the survey, including 67 males and 92 females, with an age range of 18–32 years (M = 23.55, SD = 2.46). The studies involving human participants were reviewed and approved by Fudan University Ethics Committee (FDU-SSDPP-IRB-2024-2-103). They were performed by the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. All participants in the study provided informed consent, which involves the consent to publish their data.

Experimental materials

Food packaging images

Following previous studies, the products were categorized into two broad categories: healthy and unhealthy, with a total of six products selected (see Appendix 1).

This design allows for a controlled and focused examination of the influence of color on perceived calorie content, leveraging both visual stimuli and participant self-report measures to gather data on perception dynamics influenced by packaging color (see Fig. 1).

Fig. 1.

Example of product images (red on the left and green on the right).

Healthy categories include yogurt, nuts, and fruit cereal, while unhealthy categories include potato chips, chocolate, and milk tea instant beverages. These six products were processed through Photoshop, keeping all aspects identical except for the packaging color. To maintain consistency, the RGB color values for red are: Red: 213; Green: 32; Blue: 53. The RGB color values for green are: Red: 123; Green: 225; Blue: 47.

To exclude other possible explanations such as taste appeal and attractiveness of packaging, participants were required to evaluate the taste appeal of the food, the attractiveness of the packaging, and their perception of the healthiness associated with the colors. The taste appeal was rated on a scale from 1 (not tasty at all) to 7 (very tasty). The attractiveness of the packaging was rated from 1 (not attractive at all) to 7 (very attractive).

Results (see Table 1) indicate that participants did not perceive a significant difference in taste between red and green packaging (M_red = 4.81, SD_red = 1.45; M_green = 4.80, SD_green = 1.47; t(475) = 0.05, p = 0.96), thus excluding taste appeal as another possible explanation.

Table 1.

Effect of packaging color on perceived food taste ratings.

Commodity property	Red		Green		t	p
	M	SD	M	SD
Food taste ratings	4.81	1.45	4.80	1.47	0.05	0.96

Additionally, as shown in Table 2, there is no significant difference in the perceived attractiveness of the packaging between the red and green options (M_red = 4.16, SD_red = 1.50; M_green = 4.13, SD_green = 1.48; t(475) = 0.23, p = 0.82). Therefore, the potential explanation based on the attractiveness of the packaging is also ruled out.

Table 2.

Effect of packaging color on perceived packaging attractiveness.

Commodity property	Red		Green		t	p
	M	SD	M	SD
Packaging attractiveness ratings	4.16	1.50	4.13	1.48	0.23	0.82

Caloric Estimation measurement

In this experiment, participants were asked to estimate the caloric content of the displayed foods, using the calorie content of walnuts as a reference. Specifically, participants were informed: “The calorie content of walnuts we commonly consume is 574 cal per 100 g. Please estimate the calorie content per 100 g for the food items shown in the picture above.”

Measurement of perceived healthiness

Perceived healthiness refers to consumers’ immediate judgment on the healthiness of a food item. This was measured using two items: perceived healthiness of the food (1 = very unhealthy, 7 = very healthy) and perceived increase in body fat after consuming the food (1 = very little, 7 = very much). The scores for perceived increase in body fat were reverse-scored and then averaged with the perceived healthiness score to construct a healthiness variable for the food (α = 0.787), where higher scores indicate greater perceived healthiness.

Experimental procedure

Study 1 employed a questionnaire method. Participants were instructed: “Hello: Thank you very much for your participation. We are currently conducting a study on food packaging. Please fill out the questionnaire on your phone or computer based on your actual situation, which will take about 5 minutes of your time. We solemnly promise that all data is anonymous and will only be used for this research.” Participants were first required to fill out personal information, then view product images presented in the questionnaire, estimate the calorie content of the products based on the reference calorie information provided, and answer questions about their perceived healthiness of the food. Subsequently, participants evaluated the taste of the food (1 = not tasty at all, 7 = very tasty), the attractiveness of the packaging (1 = not attractive at all, 7 = very attractive), and the healthiness perception related to the color (measured by the item “Color is related to people’s physical and mental health” (1 = strongly disagree, 7 = strongly agree)). To avoid practice and fatigue effects, the order of image presentation was balanced as “unhealthy-healthy-unhealthy.”

The study distributed 159 questionnaires, retrieved 159 effective responses, and then processed the data and performed statistical analysis.

Results

Differences in calorie Estimation

An independent sample t-test was conducted on calorie estimations (as shown in Table 3), revealing significant differences between the unhealthy food items in red and green packaging (M_red = 675.06, SD_red = 1052.99; M_green = 478.69, SD_green = 394.07; t(475) = 2.69, p < 0.01). Importantly, participants perceived that the calorie content in red packaging was indeed higher than that in green packaging, consistent with the predictions of this study. However, there was no significant difference in calorie estimations between different packaging colors for healthy food items.

Table 3.

Effect of packaging color on food calorie estimations.

Commodity property	Red		Green		t	p
	M	SD	M	SD
Unhealthy	675.06	1052.99	478.69	394.07	2.69	< 0.01
Healthy	450.49	529.50	382.40	357.85	1.64	0.10

Mediating role of perceived healthiness

Following the recommendations of Hayes³³, this paper employs the Bootstrap method to test the mediating role of perceived healthiness in the effect of red and green colors on food calorie estimation. Using packaging color as the independent variable, perceived healthiness of the food as the mediator, and calorie estimation of the food as the dependent variable. A Bootstrap sample size of 5000 was set, and bias-corrected methods were applied with a 95% confidence interval. The results, as illustrated in the figure, show that the total effect of red and green colors on calorie estimation for the unhealthy group was significant (β = − 0.2460, p = 0.0071). The significance persisted even after controlling for the mediator (β = − 0.2167, p = 0.0167). The mediating role of perceived healthiness was significant, with an estimated mediation effect size of − 0.0293, and the confidence interval did not include zero (LLCI = − 0.0741, ULCI = − 0.0034). The proportion of the mediation effect relative to the total effect was calculated to be 11.90%, indicating the effect size of health perception (see Fig. 2).

Fig. 2.

Mediating role of perceived healthiness of food. Note: * indicates p < 0.05, ** indicates p < 0.01, *** indicates p < 0.001.

Discussion

Impact of food packaging color on calorie Estimation

Study 1 results indicate that for unhealthy foods, participants perceived the calorie content in red packaging to be higher than that in green packaging. However, no significant differences in calorie estimation were found between different packaging colors for healthy foods. Perceived healthiness of food mediated this effect, aligning with the hypotheses of this research.

The influence of red and green colors on calorie estimation is attributed to the enhancement of the perception of unhealthy attributes in foods by the red color. Specifically, for unhealthy foods, red color intensifies the perception of unhealthiness, leading to an overestimation of calorie content. However, for healthy foods, which are inherently perceived as healthy, the impact of red and green packaging on their perceived healthiness is minimal, hence the color does not affect calorie estimation for healthy foods.

Limitations and future research directions

While this study provides insights into the impact of food packaging color on caloric estimation, several aspects warrant further discussion.

First, we focused on perceived healthiness as the key mediator, given its well-documented influence on caloric judgments. Prior research suggests that consumers often estimate calorie content based on their perception of a food’s healthiness rather than its actual nutritional information. However, we acknowledge that perceived indulgence—the extent to which a food appears rich or pleasurable—may also influence caloric estimation. Future studies could explore whether indulgence and healthiness function as parallel mediators, offering a more comprehensive perspective on how packaging color shapes calorie judgments. Secondly, our results indicate that packaging color influenced calorie estimation but did not significantly affect packaging attractiveness, suggesting that color effects are not driven by general aesthetic appeal. However, we must consider the real-world implications of our finding that packaging attractiveness was rated as neutral (neither highly attractive nor unattractive). In commercial settings, packaging is deliberately designed to be visually appealing to attract consumer attention and drive purchase decisions. The neutral attractiveness of our stimuli may mean that our results underestimate the true impact of color when paired with highly attractive packaging, which could either amplify or mask color-driven perceptions of calorie content. This suggests that the color effects observed in this study might be less pronounced or differ in real-world contexts where aesthetic appeal plays a stronger role in shaping consumer behavior. This limitation highlights a potential gap between our experimental findings and practical marketing scenarios, urging caution in directly applying these results to commercial packaging design. Thirdly, the caloric estimation task required participants to compare foods to a 100 g walnut reference, which may have introduced complexity or bias due to walnuts’ unique nutritional properties. Reflecting on the real-world significance of this choice, we recognize that using walnuts as a reference may not align with how consumers typically estimate calories in everyday life, where they often rely on intuitive judgments or general knowledge rather than specific benchmarks. This methodological decision could have influenced participants to anchor their estimations in a way that does not fully reflect natural decision-making processes, potentially skewing our results. Consequently, the calorie estimations reported here may not fully capture the spontaneous perceptions consumers form in real shopping environments, limiting the direct applicability of our findings to practical contexts. Moreover, the measure of perceived weight gain, intended to capture intuitive beliefs about food-related health consequences, may not fully align with physiological reality. Considering the practical implications of this measure, we acknowledge that assessing perceived body fat increase may tap into subjective biases or stereotypes about food rather than objective health outcomes. In real-world settings, consumers’ immediate judgments of weight gain might misguide their dietary choices, as these perceptions may not correspond to actual nutritional impacts. This discrepancy implies that our findings on perceived healthiness reflect subjective consumer beliefs rather than accurate health assessments, which could affect the interpretation of how color influences health perceptions in everyday life. This limitation suggests that our results should be viewed as indicative of psychological heuristics rather than direct predictors of health-related behavior. Lastly, while we categorized popcorn as an unhealthy food, perceptions of its healthiness can vary depending on preparation methods. Future studies could explore how different formulations (e.g., buttered vs. air-popped popcorn) affect health judgments and calorie estimations.

By addressing these considerations, future research can further refine our understanding of how visual cues influence consumer food perceptions, providing deeper insights into packaging design and consumer decision-making.

Study 2: color and health perception manipulation and food consumption

Study 2 employed a 2 (Color: Red vs. Green) × 2 (Health Perception Manipulation: Related vs. Unrelated group) between-subjects design.

Experimental purpose and hypotheses

In Study 1, we confirmed that food packaging color influences consumers’ calorie estimations for unhealthy foods. Using VR technology, Study 2 aims to further examine the mechanism by which color influences unhealthy food choices and to explore how to guide consumers towards healthier food consumption.

Specific hypotheses proposed are:

H3: For unhealthy foods, the association of the red color with unhealthiness will lead to an overestimation of calories in red-packaged foods. When manipulating the “Color and Health Unrelated,” the effect of color on calorie estimation will disappear in the manipulated group.

H4: Compared to the control group, the number of food choices will increase in the manipulated group where “Color and Health are Unrelated.”

Participants

A total of 120 participants were involved in the experiment, including 41 males and 79 females, with an age range of 17–28 years (M = 19.57, SD = 2.40). The studies involving human participants were reviewed and approved by Fudan University Ethics Committee (FDU-SSDPP-IRB-2024-2-103). They were performed by the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. All participants in the study provided informed consent, which involves the consent to publish their data.

Experimental materials

VR hardware equipment

The VR device used was the HTC Vive, released in 2015, featuring a 90 Hz refresh rate and accompanied by two wireless controllers (see Fig. 3). The scene was constructed using Unity3D version 5.3.x.

Fig. 3.

VR hardware equipment.

Health perception manipulation materials

For the group where color is related to health, participants read the following brief article: “Color is a visual effect produced by the interaction of our eyes, brain, and life experiences, representing a perception of objective phenomena. Color carries important psychological significance. In food consumption studies, it has been found that color relates to health. For example, red can induce feelings of tension and anxiety, while green is associated with feelings of lightness, hope, and better health.”

In the group where color is unrelated to health, the article read by participants stated: “Color is a visual effect produced by the interaction of our eyes, brain, and life experiences, representing a perception of objective phenomena. Although marketers in the food industry use color to promote their products, scientific studies show that color has no relation to health.”

To control for extraneous variables, both articles were of the same length. To enhance the authenticity of the information, the articles mentioned that they were sourced from Guokr (a popular science website) and included references to the original English literature.

Food packaging images

In Study 2, the type of unhealthy food used was buttered popcorn. Two bags of popcorn were used, differing only in their packaging color (see Fig. 4). To maintain consistency, the RGB color values were as follows:

Fig. 4.

Popcorn (Red packaging on the left, green packaging on the right).

Red packaging: Red: 213; Green: 32; Blue: 53.

Green packaging: Red: 123; Green: 225; Blue: 47.

This setup ensures that any differences in participant responses can be attributed to the color of the packaging rather than differences in the packaging design or product appearance.

Experimental procedure

All participants were randomly assigned to one of four groups. After being briefed on the experiment, they were assisted with putting on the VR headset and were informed about the basic interaction operations within the virtual reality system.

Experimental Task: The annual scholarship application and evaluation process kicked off. Over the past year, you have worked hard in both your studies and practical activities, meeting the criteria for the scholarship application. Although you believe you performed well last year, your peers are also excellent and actively competing for the scholarship. After a tense and anticipatory week, you finally see your name on the scholarship list announced this morning. To reward yourself, you decide to buy some tasty snacks, and popcorn—a popular snack among consumers—catches your eye, particularly the new flavor launched by Brand L. Your task is to find the ‘Egg Flower Corn’ popcorn on the shelf and assist Brand L with evaluating this new product.

Once equipped with the VR headset and entered into the simulated shopping environment, participants encountered either the health-related or unrelated color manipulation texts. Next, participants virtually picked up and examined the popcorn. To ensure the quality of observation, the system was programmed to allow any number of popcorn bags to be added to the shopping cart for purchase after being held for ten seconds.

At the end of the session, participants were required to complete a questionnaire on a computer. The questionnaire included items on calorie estimation, tastiness, health perception, attractiveness of the packaging, and color health perception, using a Likert scale ranging from 1 (strongly disagree) to 7 (strongly agree). The color health perception was specifically measured by the item: “Color is related to people’s physical and mental health.” Participants then filled out their personal information, marking the conclusion of the experiment. (Link to the questionnaire: https://www.wjx.top/jq/31317197.aspx.

Results analysis

Manipulation check for color health perception

First, we conducted a manipulation check for color health perception (see Table 4). This involved using the color health perception manipulation and the red-green group as fixed factors in an ANOVA on color health ratings. The results showed a significant effect of the color health perception manipulation on the health ratings (M unrelated group = 3.83, SD unrelated group = 0.20; M related group = 4.82, SD related group = 0.21; F(1, 110) = 11.51, p < 0.01), while the effects of the red-green group (F(1, 110) = 1.13, p = 0.29) and interaction (F(1, 110) = 0.01, p = 0.94) were not significant. This confirms the effectiveness of the color health perception manipulation.

Table 4.

ANOVA results for the effect of packaging color and health perception manipulation.

Variable definitions	Df	MS	F	p
Color	1	2.63	1.13	0.29
Color health perception manipulation	1	26.84	11.51	0.001
Color * color health perception manipulation interaction	1	0.02	0.01	0.935

Impact on calorie Estimation

Next, we examined the interactive effect of color health perception manipulation and the red-green group on the calorie estimation of popcorn (see Table 5). The color health manipulation and red-green group were used as fixed factors with popcorn calorie estimation as the dependent variable in a full model ANOVA. The results showed that the main effect of the red-green group was not significant (M red = 621.56, SD red = 39.39; M green = 556.57, SD green = 39.39; F(1, 110) = 1.36, p = 0.25), and the main effect of the color health manipulation was also not significant, F(1, 110) = 1.49, p = 0.22.

Table 5.

Full ANOVA model results for the effect of packaging color and health perception manipulation on calorie estimation.

Variable definitions	Df	MS	F	p
Color	1	116125.46	1.36	0.25
Color health perception manipulation	1	127449.53	1.49	0.22
Color * color health perception manipulation interaction	1	9270.69	0.11	0.74

Impact on the quantity of food choices

Finally, we examined the interactive effect of color health perception manipulation and the color group on the quantity of product choices (see Table 6). Color health manipulation and the red-green group were used as fixed factors, with the quantity of product choices as the dependent variable in a full model ANOVA. The results showed that the main effect of color health manipulation was significant (M related = 2.96, SD related = 0.30; M unrelated = 4.07, SD unrelated = 0.31; F(1, 110) = 6.67, p = 0.01), while the main effect of the red-green color was not significant, F(1, 110) = 1.24, p = 0.27.

Table 6.

Full ANOVA model results for the effect of packaging color and health perception manipulation on product choice quantity.

Variable definitions	Df	MS	F	p
Color	1	3.10	0.61	0.44
Color health perception manipulation	1	33.86	6.67	0.01
Color * color health perception manipulation interaction	1	6.30	1.24	0.27

Discussion

Study 2 tested the theoretical mechanism proposed in this paper by manipulating color health perception, confirming that red enhances calorie estimation only when people associate color with health. When people do not associate color with health, the effect of red (vs. green) on increasing food calorie estimates disappears. Additionally, after manipulating color health perception, the quantity of products chosen by the group that considered color as unrelated to health was greater than that by the group that considered color related to health. An important implication for food consumption is that strengthening the association between color and health can reduce the consumption of unhealthy foods.

General discussion

The impact of food packaging color on caloric Estimation

Results from Study 1 indicate that for unhealthy foods, participants perceived the caloric content of food items in red packaging to be higher than those in green packaging. This perception did not significantly differ among healthy foods, aligning with our hypothesis. Red is associated with avoidance motivation¹⁷, which can lead to reduced consumer purchases of such food items. According to Association Theory²⁸, frequent co-occurrence of two events leads to a predictive association between them. Hence, red is often linked with unhealthy, high-calorie foods, particularly evoking this association in the context of unhealthy foods.

In essence, the influence of red and green colors on caloric estimates stems from red enhancing the perceived unhealthiness of foods. Specifically, for unhealthy foods, red intensifies the perception of their unhealthiness, leading to an overestimation of their caloric content. However, for healthy foods, which are inherently considered healthy, the impact of red and green packaging on perceived healthiness is minimal, thus the colors do not affect caloric estimates. This pattern suggests that pre-existing beliefs about a food’s healthiness may moderate the influence of packaging color. Since healthy foods are already perceived as low-calorie, the effect of color cues becomes less pronounced. This highlights the role of cognitive biases in consumer decision-making, where prior knowledge about food categories can override external visual cues. Additionally, individual differences such as nutrition knowledge and dietary habits may further influence how consumers interpret packaging colors, warranting further investigation.

Furthermore, while our findings demonstrate a statistically significant effect of packaging color on calorie estimation, the effect sizes were relatively small. This indicates that packaging color is one of several factors influencing calorie perception rather than a dominant determinant in real-world settings. Other elements, such as branding, nutritional labels, and personal dietary habits, likely interact with color cues to shape consumer perceptions. Future research could explore these interactions to gain a more comprehensive understanding of how multiple packaging elements jointly influence food choices. Moreover, cultural differences in color perception could also play a role, as the meanings associated with red and green may vary across different consumer groups, affecting their impact on food choices.

These findings have practical implications for food manufacturers and policymakers. Given that red packaging increases calorie perception and may deter purchases of unhealthy foods, regulatory bodies could consider leveraging color strategies in front-of-pack labeling to subtly guide healthier consumer choices. For instance, mandatory use of red for high-calorie, unhealthy foods and green for healthier alternatives could reinforce intuitive health perceptions, helping consumers make more informed dietary decisions. Additionally, food manufacturers aiming to promote healthier products might utilize green packaging to enhance perceived healthiness, potentially influencing purchasing behavior. Future research could explore the extent to which these color-based interventions impact real-world food choices.

The mediating role of perceived healthiness

The overall effect of packaging color on caloric estimates for unhealthy food groups was significant, with perceived healthiness of the food playing a mediating role. This observation is consistent with our hypothesis. Numerous studies have examined the link between the perceived healthiness of food and caloric estimates. Carels, Konrad, and Harper found that foods considered healthy or beneficial for weight loss are typically underestimated in calorie content, whereas those perceived as unhealthy or detrimental to weight loss are overestimated²⁴. Previous research suggests that consumers heuristically use perceived healthiness to estimate caloric content, tending to overestimate the calories in unhealthy foods³⁴. Considering the link between perceived healthiness and calorie perception, along with the association of red with unhealthy food, red lowers the perceived healthiness of food, consequently leading to an overestimation of its caloric content.

From an application perspective, these findings suggest that food labeling regulations could incorporate design elements that reinforce accurate calorie perception. For example, in addition to color, integrating clear nutritional seals or warning labels on red-packaged unhealthy foods might further strengthen consumer awareness. Policymakers and manufacturers could experiment with multi-faceted packaging strategies that combine color with explicit health-related messaging to maximize the effectiveness of front-of-pack labeling initiatives.

The influence of manipulating color-health perceptions

The fundamental logic of this paper is the association of red with unhealthy food, leading to the belief that food items in red packaging are unhealthy, which in turn results in an overestimation of caloric content²⁷. Although research indicates that there is a general acknowledgment of the relationship between color and health³⁵, this study hypothesizes that if the notion “color is irrelevant to health” is activated, the impact of color on caloric estimation will disappear. In Experiment 2, we further tested this theory by manipulating individuals’ perceptions of color and health.

Further research into unhealthy foods shows that compared to green, red is associated with unhealthiness and thus leads to an overestimation of caloric content in red-packaged foods. When manipulating the perception that “color is irrelevant to health,” the impact of color on caloric estimation disappeared within the manipulated group. Moreover, compared to the control group, the number of food choices significantly increased in the manipulated group where “color is irrelevant to calories,” suggesting that emphasizing the link between color and calories can guide healthier consumer food choices.

These insights highlight the potential for public health campaigns to educate consumers about the psychological influence of packaging color on food perception. If individuals become more aware of how color biases their judgment of calorie content, they may make more rational food choices based on actual nutritional information rather than heuristic cues. Future research could explore the effectiveness of consumer education programs in reducing color-based biases in food perception, particularly in populations prone to making impulsive food choices.

Our study utilized virtual reality to examine the effects of packaging color on calorie estimation and perceived healthiness, providing a more immersive experience compared to traditional 2D image-based studies^35,36. Unlike static images, VR allows participants to engage with food items in a spatially realistic setting, potentially enhancing ecological validity. Traditional studies on food packaging color, such as Su and Wang (2024) and Berthold, Guion, and Siegrist (2024), have primarily used 2D images, requiring participants to imagine their purchasing decisions^35,36. Despite methodological differences, our VR-based findings align with their results, showing that red packaging increases calorie estimations and green packaging enhances health perceptions. However, while Su and Wang (2024) linked color effects to purchase intentions and Berthold et al. (2024) found that sustainability perceptions outweighed healthiness in driving consumption decisions, our study specifically examined caloric estimation and the mediating role of perceived healthiness, offering a complementary perspective on consumer decision-making. Despite these advantages, VR still has limitations, as it lacks real-world shopping elements such as store layout, peer influence, and promotional cues, which may shape consumer behavior. Additionally, the absence of tactile and sensory feedback in VR may limit its ecological validity³⁶. To address these concerns, future research should validate these findings in natural shopping environments using eye-tracking and consumer ethnography to better capture real-world decision-making. Comparing results across VR, 2D image-based studies, and in-store experiments would further clarify how different methodologies influence consumer responses to packaging color and related perceptions.

Limitations and future research directions

In the realm of sensory marketing, color exerts a pivotal influence on consumer decisions. Empirical evidence supports the existence of a “seven-second rule” in product selection, where consumers are able to form preferences within a mere seven seconds when faced with multiple options. During this critical window, the influence of color is profound, accounting for 67% of the decision-making process and significantly shaping consumer preferences. Consequently, the choice of packaging color is instrumental in influencing the ultimate purchasing decisions of consumers.

This article employs virtual reality technology to investigate the effects of red and green packaging colors on the estimation of food calories. The findings robustly affirm the foundational effects, mediating mechanisms, and attitudinal moderations associated with these colors. Despite these advances, several avenues for future research remain open.

Firstly, while the study posits a causal link between packaging color and perceived healthiness, the possibility of a bidirectional relationship suggests the need for further investigation to elucidate the interplay between these variables. Secondly, while VR technology offers methodological advantages, its applicability to real-world shopping environments remains a concern. Prior research suggests that consumer behavior in experimental settings may not fully align with real-life purchasing patterns. Future research should explore ways to enhance the ecological validity of VR-based shopping experiments, such as integrating real-time behavioral data or combining VR with field studies. Additionally, advancements in immersive technologies, such as augmented reality (AR) and mixed reality (MR), may help bridge the gap between experimental and real-world shopping contexts. Thirdly, the absence of eye-tracking measures limits our ability to precisely determine how participants allocate visual attention when evaluating packaging. Eye-tracking research has shown that fixation duration, gaze patterns, and visual saliency significantly influence consumer perception and decision-making³⁷. Future studies could integrate eye-tracking technology to complement behavioral measures, offering a more nuanced understanding of attentional focus in virtual shopping environments.

Moreover, the research was confined to red and green packaging colors. While this selection aligns with our theoretical framework, the exclusion of other potentially relevant hues (e.g., blue or yellow) and insufficient control of color saturation/brightness parameters constrain the generalizability of findings. Future work should systematically vary chromatic properties while expanding the color spectrum. Additionally, the participant demographic was predominantly university students from Shanghai, and the lack of assessment regarding participants’ product familiarity leaves open questions about how dietary habits and prior exposure may influence responses. Incorporating demographic diversity measures and pre-screening questionnaires could strengthen causal interpretations. Additionally, the experimental materials used in this study, particularly the food packaging images, lack the realism often seen in more recent studies (e.g., Hallez et al., 2023), where packaging designs closely mimic commercial products. While our design prioritized control over extraneous variables by isolating color effects, we acknowledge that this reduced realism may limit the generalizability of findings to real-world shopping contexts. Future research should incorporate more realistic packaging designs to better reflect commercial environments and assess their impact on consumer perceptions.

Methodologically, while color served as our focal variable, we acknowledge that packaging design elements like nutritional seals, typography, and graphic components may interactively shape health perceptions. The current design intentionally isolated color effects, but future investigations could adopt factorial designs to disentangle these interrelated factors.

Conclusion

Study 1 used survey methods to preliminarily confirm that red enhances calorie perception while ruling out other possible explanations such as taste and packaging attractiveness. It also verified that red (vs. green) increases calorie estimates, an effect mediated by perceptions of food healthiness. Additionally, the study acknowledged a general awareness of the association between color and health, providing robust support for the predicted basic effects and mediation. Study 2 further investigated unhealthy foods, finding that compared to green, red is associated with unhealthiness, thereby leading to higher calorie estimates for red-packaged foods. When manipulating the irrelevance of color to health, the impact of color on calorie estimates disappeared in the manipulated group, leading to an increase in food choice quantity compared to the control group where color and calorie associations were deemed irrelevant.

These studies collectively underscore the significant role of color in shaping calorie estimation and health perception, emphasizing its relevance in food marketing and consumer decision-making. However, while our findings highlight the power of color cues, it is important to recognize that color is just one of many factors influencing consumer choices. Future research should validate these effects in real-world shopping environments and explore interactions with other packaging attributes, such as branding, labeling, and sensory features. Additionally, adopting a multisensory and contextual approach—considering elements like texture, typography, and product placement—would provide a more holistic understanding of packaging design’s impact on consumer behavior.

From a practical perspective, these insights suggest that marketers should strategically leverage color psychology in packaging design, particularly in health-oriented marketing strategies, while also considering how other packaging elements interact with color to shape consumer perceptions and choices.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

Q.T. and Y.D. conceptualized the study and designed the research framework. Y.D. conducted the data collection and performed the statistical analyses. J.G. prepared the visualizations and contributed to the interpretation of the results. Q.T., Y.D. and J. G. wrote the main manuscript text. All authors reviewed and approved the final manuscript.

Data availability

The datasets generated and/or analyzed during the current study are not publicly available due to confidentiality agreements but are available from the corresponding author （18210730119@fudan.edu.cn） on reasonable request.

Declarations

Competing interests

The authors declare no competing interests.