The price penalty for red meat substitutes in popular dishes and the diversity in substitution.

Life cycle assessments (LCA) often highlight the environmental and health benefits for consumers if western diets substitute red meat. However, the specific trade-off consumer face when asked to substitute a red meat dish is scarcely researched, often neglecting the bouquet of substitution options and/or the price component involved. Four substitution strategies are evaluated within an individually adapted choice based conjoint: the substitution by (1) the same red meat dishes with a halved meat portion size, (2) novel plant-based products that mimic the functionality and taste, (3) authentic plant-based components that just mimic the functionality, and (4) vegetarian dishes that just neglect the meat component if still familiar to consumers. The analysis is executed for three popular red meat dishes to account for consistency across meal scenarios, namely Meatballs, Spaghetti Bolognese and Sausage Buns. The analysis is sensitive to red meat consumption habits to better understand the preferences of consumers that can actually substitute a red meat intake.

Introduction

I enjoy eating beef, but I fear we have to eat less. Beef production requires roughly 36 (±13) times the feed mass than the edible meat generated [1]. The conversion rate points to the amount of land resources required to provide food for human consumption. The carbon footprint of 1 calorie derived from beef is estimated at 22 g CO2-equivalent in contrast to 0,05 g for 1 calorie derived from pulses [2]. The widely noted EatLancet report considered the health and environmental impacts of diets and recommends roughly 2.6 kg of beef or lamb per year [3], while within the EU-27 about 15 kg are available for consumption each year [4]. From the report follows that the current level of red meat consumption is not sustainable, threatens our health and depletes our means of production. Nevertheless, red meat consumption is deeply rooted in western dietary patterns [5]. Consumers are often faced with tasteful red meat variations inherent to western food cultures.

This status of red meat in western food cultures makes red meat prevalent, especially in food settings that allow only for a limited number of offerings such as when eating-out. About 7% of all EU-expenditures are spend on the out-of-home food market [6]. The share is growing each year [6]. This out-of-home market is characterized by suppliers that have to prioritize food options, as opposed to a supermarket that approximately offers 20000 products. Such suppliers rightfully select popular dishes that the consumer is willing to pay a reasonable amount for. In consideration of red meat’s externalities, the question needs to be addressed how much consumers are less willing to pay for substitutes and consequentially how much worse off are out-of-home suppliers if they start to prioritize substitutes.

Climate researchers and the life-cycle assessment (LCA) literature have analysed foods with respect to its environmental impact and the utility of a change, but with little consideration for adequate substitutes and often failed to understand consumer’s trade-offs [7]. On an aggregated dietary level there is a rich literature on the drivers of adoption of purely vegetarian diets (literature reviews by [8,9]), including an increasing number of studies on strategies that may help to nudge consumers towards plant-based, i.e. vegetarian diets (literature review by [10]). However, the vast majority of consumers does not identify with a diet that strictly prohibits red meat. In line with dietary recommendations, such as the EatLancet report, consumers should be supported in cutting back on red meat intake not necessarily in stopping altogether. So, diets low in meat or daily choices against meat enable consumers’ transition to healthier and more sustainable food choices, optionally vegetarian diets at some point. In this context, we analyse consumer behaviour on a dish or ingredient level.

A few studies have analysed meat preferences within dish compositions. These studies evaluated specific substitution options that we group in four categories:

Reduced meat portion size (a): Globally, reduced meat portion sizes are more popular than western food culture might suggest. In East Asia, the servings of meat are an essential part of the food culture while the quantity is low in most dishes, i.e. meat fulfills a flavouring function rather than providing calories to human consumption [11]. With respect to consumer acceptance, a meat reduction in Mexican cuisines adversely affects consumer liking, which does not hold for Indian cuisines [12]. This confirms the food culture component when designing substitutes. As international cuisines are increasingly adopted in western countries, the promotion of some of the cuisines presents an opportunity. However, it also highlights the difficulty of reducing portion sizes of existing western dishes. In a Dutch restaurant setting, a reduction from 210 to 180 g of meat in a meat-centred dish preserved most of the satisfaction previously experienced [13]. This points to the importance of subtle changes in order to let “meat reduced portion sizes” grow on consumers. Generally, caterers and restaurants are often reluctant to reduce the share of red meat, because they feel their customers judge the quality of the food based on the quantity of meat.

Novel plant based meat resembling products (b): The market for textured meat substitutes (2) in western Europe is growing at more than 10% annually since 2014 (Euromonitor 2018). Such substitutes can be integrated with ease in common meat dishes [14], as they hardly require recipe changes or any new preparation skills. Nevertheless, option (b) is a niche market unfamiliar to most consumers [15], often assumed to provide inferior taste [16]. A study on burgers estimated the average WTP for a beef burger around 13.5 USD, while the plant-based texture meat burger received an average WTP of 4.25 USD [17]. Although the product concepts of (b) are well accepted among meat eaters, considerable reformulation efforts will still be necessary to attract more consumers and convey an acceptable “meaty flavor” [18].

Authentic plant-based products (c): Consumers concept of authenticity is not always identical between food cultures. It includes rather a lower amount of processing and the plant based component has typically an established role within a dish composition. These components do not mimic the taste of meat but can obtain a similar functional role in the dish [19]. For example, Falafel may substitute Meatballs and grain burgers may replace meat-burger patties. Here, functionality refers to the way the dish is designed to be well balanced in the eyes of consumers. The functional component does not necessarily provide a nutritional profile that resembles the meat component. Many variations of the option (c) exist for decades but have not been able to mainstream into the dietary patterns of meat-eaters in the west. Nevertheless, several consumer segments prefer the idea of meat substitution with authentic alternatives over meat resembling products [15].

Familiar vegetarian meal that simply neglects the meat (d): In some instances, the meat component is just neglected (4) and the dish remains familiar and authentic to consumers. Consumers are used to these dishes but they are often thought of as less appealing or low budget alternatives.

Conclusively, none of the substitution strategies is currently on an eye level with red meat consumption. The substitution categories have also been described in more detail in a mapping review by Boer and Aiking [5]. The review highlights how change strategies should build on the availability of a range of substitution options in order to give consumers flexibility. Unfortunately, consumer researchers have predominantly focused on just one category and denied consumers flexibility in the substitution task. A parallel analysis can highlight relative potentials, particularly with heavy meat eaters that are asked to substitute. Consumer research needs to better identify the type of consumers willing to substitute with any category, with a specific one and with none. Additionally, most substitution studies neglect the economic perspective, such as estimating WTP differences, which can make it difficult to communicate the results to policy makers and caterers.

This study fills the gap and accounts for a multitude of options to substitute. An utility framework for an individually adapted choice based conjoint (CBC) will be applied, where consumers are asked to decide between the set of substitution options and an applicable popular red meat dish. The analysis explores substitution preferences across three popular dishes, i.e. three case studies. Further, we calculate the carbon footprint of each evaluated dish to account for trade-offs between environmental benefits and consumers’ WTP. The diversity of the substitution categories is typically not available in the out-of-home market that needs to prioritize dishes. A better understanding of the price penalty that substitutes invoke can help progressive food business and researchers to design more promising interventions on who and how to enable red meat substitution.

Research objective

Based on the described substitution pathways two main research objectives are addressed: 1. An estimation of the price penalty (lower average WTP) for the substitution options, 2. An estimation of the price penalty sensitive to past consumption levels of the red meat dish at hand. While the former is of interest to caterers and restaurants that want to maximize revenues, the latter emphasizes frequent eaters that can actually substitute the red meat dish. Thereby, it provides a societal perspective on the potential of substitution, if substitutes were readily available in the market. Empirical evidence on the WTP for substitution pathways is still limited. The out-of-home market predominantly supplies the red meat dishes. A WTP analysis estimates beef burgers at almost three times the WTP of plant based burgers [17]. Other studies have shown how authentic alternatives or reduced meat portions can reduce meal satisfaction or sensory liking [12,13,18]. Therefore, we hypothesize a price penalty for all the substitution options (Table 1, H1), which is more pronounced for heavy red meat eaters because higher consumption of red meat is associated with a lower acceptance of substitutes [15] (Table 1, H3).

Table 1

Design planner.

Question	Hypothesis (H1 to H4)	Sampling plan	Analysis plan	Interpretation given different outcomes
Is there a price penalty for red meat substitution options?	U(RMD) > U(S1,S2,S3,S4)	Quoted consumer sample representative of age, gender and income	Model 1	confirmed if consistently shown for all 3 RMD cases
Is the price penalty less severe for any of the substitution options?	U(S1,S2,S3,S4)≠ U(S1,S2,S3,S4)		Model 1	confirmed if at least one substitution option provides consistently greater or lesser utility across all 3 RMD cases
Is the price penalty more pronounced if consumers frequently eat the red meat dish?	μ[U(RMD) -U(S1,S2,S3,S4)]> U(RMD)- U(S1,S2,S3,S4)		Model 1 and 2	confirmed if consistently shown for all 3 RMD cases
Is the price penalty less severe for any of the substitution if consumers frequently eat the red meat dish?	μU(S1,S2,S3,S4)≠ μU(S1,S2,S3,S4)		Model 2	confirmed if at least one substitution option provides consistently greater or lesser utility across all 3 RMD cases

U(X) = average utility derived from option X, S1-4 = substitution option 1 to 4, RMD = popular red meat dish, μ = a weighting matrix defined by the frequency consumers eat the RMD.

As we have previously explained how the preferences between substitution options are hardly understood, yet, we speculate that the price penalty is not equal for all substitution options (Table 1, H2). This implies an ordinal consumer preference structure, which also holds for the preference structure of heavy red meat eaters (Table 1, H4). An ordinal structure would be of interest to caterers and researchers faced with designing substitution interventions. However, it should be complemented by an idea of the type of consumer segments interested in a specific substitution category. We supplement the research objectives by exploratory research on the relationship of consumer characteristics with a preference for each substitution option. Each hypothesis is confirmed if a statistically significant difference (5%-level) is consistently found across all 3 cases of popular red meat dishes (Table 1).

Further, the carbon footprint of each dish is approximated, as one environmental indicator that urges the substitution of red meat. The consideration of the CO2-footprint helps to indicate whether a CO2 tax, which is broadly discussed, would be able to compensate for the price penalty between any of the dishes. Therefore, the estimated WTP results are complemented by a report of the CO2 tax-level demanded to level consumer preferences.

Study design

The proposed study is a cross sectional survey experiment in the form of an individually adapted choice based conjoint, where participants evaluate hypothetical food choices in an out-of home lunch setting. Participants evaluate substitution options against popular red meat dishes, while the design is sensitive to heterogenous WTP among consumers.

Three popular red meat dishes

To apply the previously presented substitution categories to tangible cases of food choices, we introduce three popular red meat dishes (RMD):

(a) Spaghetti Bolognese, as a “mixed dish” for which meat is not the main meal component [5]. The quantity of meat is not overly visible and consumers do not necessarily recognize a reduction of meat within the sauce. (b) Meatballs with rice and peas, as a “meat-centered” dish where plant-based ingredients are typically considered a side-dish [5], and (c) buns with butter and sausage, which presents a snack option for lunch instead of a warm meal decision (Table 2). The red meat dishes are well known. European consumers have developed a habitual use of them.

Table 2

Experimental dishes and their CO2-footprint per portion.

Main ingredients/weight per portion (RDM)	CO2- footprint kg CO2 eq/kg	Red meat Dish	Substitute (1)	Substitute (2)	Substitute (3)	Substitute (4)
		Spaghetti Bolognese	… ½ minced meat Bolognese	… Soy-based minced meat	Lentil Bolognese	Spaghetti Napoli
minced beef/166 g	9,2	1,53	0,77	X	X	X
tomato puree/100 g	1,8	0,18	0,18	0,18	0,09	0,23
pasta/166g	0,7	0,12	0,12	0,12	0,12	0,12
lentils/50 g	1,2	X	X	X	0,06	X
textured vegetable protein (soy)/166g	1,0	X	X	0,17	X	X
Total	N.A.	1,83	1,06	0,46	0,27	0,34
		beef topping for 2 buns with butter	½ thick-ness of topping …	vegan sausage topping …	Sliced Emmentaler cheese …	N.A.
bun/2x50 g	0,7	0,07	0,07	0,07	0,07	0,07
beef topping/2x20 g	7,9	0,32	0,16	X	X	X
butter/2x 20 g	9	0,36	0,36	0,36	0,36	0,36
vegan sausage/2x20g	1,7	X	X	0,07	X	X
Emmentaler cheese/2x20g	6	X	X	X	0,24	X
Total	N.A.	0,75	0,59	0,50	0,67	0,43
		beef meatballs with rice and peas	½ portion meatballs …	Soy-based patties …	Falafel …	N.A.
beef meatballs/200g	9,2	1,84	0,92	X	X	X
soy patty/200g	1,1	X	X	0,22	X	X
canned chickpeas/200g	1,3	X	X	X	0,26	X
Rice/50 g	3,1	0,155	0,155	0,155	0,155	0,31
canned Peas/50 g	1,7	0,085	0,085	0,085	0,085	0,17
Total	N.A.	2,08	1,16	0,46	0,50	0,48

Portion sizes are informed by recipes from a popular German cooking website: Chefkoch.de, pictures are sourced from pixabay.com (only for non-commercial use), CO2 footprints are based on estimations of the IFEU-institute [20]. Minor ingredients and means of food preparation are neglected.

For the given dishes CO2 footprint estimations are available (Table 2). The IFEU Institute supplied CO2-footprint averages for the major ingredients of the dishes based on comparable value chains, capturing emission from farm to retail [20]. This allows for a calculation on whether a CO2 tax-level can change the ordinal preference structure. Different CO2 tax-levels are globally discussed, e.g. 55 € per CO2 ton (5,5 cents per kg) is planned in Germany for the energy and transportation sector [21].

Sampling procedure

A quoted consumer survey will be launched online. Participants shall be representative of Germans with internet access by age, gender and income [22]. Participants are invited to the study via a market research company who deals out a small reimbursement fee. The recruitment process allows to not inform about the particular focus of the study to avoid self-selection bias. Data quality checks include completeness and streamlining. Streamlining ensures that participants use a minimum of time on a set of questions [15]. Moreover, it monitors how participants progress through question blocks in order to exclude participants with speeding and/or systematic answering behavior. The monitoring of overall time spend on the survey becomes unnecessary. No other data exclusion criteria are planned. Budgetary constraints allow for 1000 consumers. Power calculation have been executed with a Cox model in STATA comparing a regression slope (the marginal utility for the substitution options) to a reference (the opt-out). Under the assumption of a minimum detectable effect size of 0.2, standard deviation of 0.5, power of 0.8 and a significance threshold of 0.05, 785 consumers should be surveyed. We aim for 800 valid responses. The survey will be coded with the Editix XML-Editor.

Ethical approval

The investigation is part of a work package in the research project “Key food choices and climate change”. The full project proposal has been filed for ethical approval. The ethical committee of the University of Göttingen has granted the project ethical approval on the 18.12.2018.

Choice procedure

After socio-demographic questions, consumers are introduced to the out-of-home setting. Consumers are asked to imagine a lunch routine where a facility was preselected and now they may select one out of five dishes. The dish components are named but the dishes are no further introduced because the unbiased consumer beliefs and opinions are of interest to the research objective. Before consumers face the choice sets, they are exposed to a cheap talk that explains how they should imagine the purchase situation, act as if real money would be asked of them and how consumers sometimes misinform on their preferences. Participants are required to confirm that they understood the cheap talk. The cheap talk reduces hypothetical bias [23].

The choice options are the substitution categories and the popular RMD (Table 3). Consumers are exposed to six choice tasks for each RMD (Table 3). In total 18 choice sets (6 choice-sets per choice scenario x 3 choice scenarios) are evaluated, which seems acceptable given that consumer fatigue should be lower because different meal scenarios are surveyed.

Table 3

a Attribute Design of choice based conjoint with 5 meal options (d-efficient design).

b Attribute Design of choice based conjoint with 4 meal options (d-efficient design).

Choice set	1	1	1	1	1	2	2	2	2	2	3	3	3	3	3	4	4	4	4	4	5	5	5	5	5	6	6	6	6	6
Dish [ASC]	1	2	3	4	5	1	2	3	4	5	1	2	3	4	5	1	2	3	4	5	1	2	3	4	5	1	2	3	4	5
Wait time	0	2	1	0	0	2	2	2	0	0	0	2	2	1	0	2	2	2	1	0	1	2	0	0	0	1	2	0	0	0
CO2 footprint	0	0	1	2	1	0	2	2	2	1	0	1	1	2	1	2	2	2	0	1	1	0	2	0	1	2	2	0	1	1
f.Price	3	0	0	1	3	1	3	3	3	3	3	0	0	0	3	2	2	2	0	3	0	0	2	0	3	3	0	3	0	3

d-efficiency = 1.206, waiting time [0 = 5 min, 1 = 10 min, 2 = 15 min], flexible price component in € [0 = 1, 1 = 2, 2 = 3, 3 = 4], dish [substitution option 1 to 4], co2 footprint [0 = high, 1 = not provided, 2 = low].

d-efficiency = 1.075, waiting time [0 = 5 min, 1 = 10 min, 2 = 15 min], flexible price component in € [0 = 1, 1 = 2, 2 = 3, 3 = 4], dish [substitution option 1 to 3], co2 footprint [0 = high, 1 = not provided, 2 = low].

The choice-sets include only four attributes to reduce the burden on consumers. Many attributes can cause information overload so that consumers develop decision rules based on just one or two attributes, which results in poor estimations of the remaining attributes. The four attributes are: the dish (5 levels), waiting time (3 levels), CO2-footprint (3-levels) and price (4 levels within IACBC). The choice alternatives are labelled with the dish names. Each dish occurs once per choice set (alternative specific constant). Price levels are essential to the WTP analysis and waiting time represents the value of time which matters particularly in lunch settings and hints at a convenience factor of interest to all kinds of substitution interventions. The CO2-footprint indicates just how relevant the simple naming of a footprint advantage is to the task of reducing the price penalty. The popular red meat dish is treated as no-purchase option with constant attributes, therefore the utility derived from substitutes is anchored to the utility derived from the red meat dish. Altogether, 15 levels of 4 product attributes are evaluated (Table 4).

Table 4

Product attributes and attribute levels in the IACBC.

Attribute	Description	Levels
Dish	reduced meat portion size	½ minced meat Bolognese, ½ thickness of topping, ½ portion of meatballs
	plant based meat resembling product	Soy based minced meat, Vegan sausage topping, Soy-based patties
	authentic plant-based product	Lentil Bolognese, Sliced Emmentaler cheese, Falafel
	just neglecting the meat component in	Spaghetti Napoli
	the RMD (reference)	(1) Beef sausage, (2) Spaghetti Bolognese, (3) Beef meatballs
Waiting time	Standard (reference)	5 min
	Long	10 min
	Very long	15 min
CO2-footprint	Claim of a low CO2-footprint	Low
	No information provided	?
	Claim of a high CO2-footprint	High
Price	The substitutes are subject to base and flexible price components set in IACBC design flexible price has 4 level for each dish, see also Table 6	Total price for RMD: (1) 3 €, (2) 8 €, (3) 9 € Base price levels for all substitutes to: (1) 1.5 €, to (2) 4 €, to (3) 4 €

The design of the attribute levels in each choice set is calculated with a STATA implementation of a d-efficient design based on a modified Fedorov-algorithm [24]. The STATA code is available upon request. The design assumes an utility penalty for each substitution dish in order to allow sensitive estimations at this range of values. Further, the design allows for the alternative specific constants and a fixed red meat dish option (Table 3). The choice-sets are followed by a set of questions on consumer characteristics.

The choice pricing mechanism—Individually adapted choice-based conjoint (IACBC)

We apply an individually adapted choice-based conjoint (IACBC) [25]. Regular choice-based conjoint often suffer from extreme response behavior, i.e. a substantial number of consumers have always or never selected the no-purchase option. Consequently, there is no information on when these consumers are willing to accept a substitute or when they would stop buying the substitute, which results in poor WTP estimations of such consumers. For this study, there is little indication of how low a price level has to be to persuade frequent meat-eaters to endorse a substitute. IACBC accommodates heterogeneity with very low and very high consumer WTP. IACBC discounts the prices of all the substitution options by a specific factor whenever the no-purchase option is selected and multiplies prices with a factor greater than 1 whenever one of the substitution options is selected. Additionally, the prices for the substitutes oscillate.

To illustrate the IACBC price algorithm, imagine a scenario of a consumer willing to buy any substitute at a price of 6 € or lower. The popular red meat dish is always offered at 8 €, which is a 2 € price premium. Such a consumer will select a substitute if the price drops below 6,01 €. In theory, the IACBC is also equipped to detect WTP differences between just the substitutes but is simplified here. The price of the dishes consists of two components. The base price level presents a stable minimum price level for each substitute, which is always added to the flexible price. The flexible price component is multiplied with a multiplier that follows the function: where n represents the number of shifts in direction between purchase and no-purchase decisions. z equals 1 if a substitute is selected and -1 if the no-purchase option is selected. The multiplier is set to 1 in the first choice-set. If a substitute is selected in choice-set 1, the multiplier is set to 2 and asymptotically converges to 1 (Table 5). For example, in choice-set 1 (Table 5) a substitution option has been selected, so that in choice-set 2 the price for option 1 equals: base price (4 €) + flexible price (5 €) x multiplier (2) (Table 5).

Table 5

Illustration of IACBC approach for a consumer willing to pay up to 6 € for any substitute.

				Final Price Option 1 to 4
choice-set	base Price, option 1 to 4	flexible price, option 1 to 4	multiplier	option 1	option 2	option 3	option 4	choice
1	4/5/5/4	2/3/4/5	1	6	8	9	9	option 1
2	4/5/5/4	5/4/3/2	2	14	13	11	8	5 (RMD)
3	4/5/5/4	5/2/3/4	1,2	10	7,4	8,6	8,8	5 (RMD)
4	4/5/5/4	4/3/2/5	0,72	6,88	7,16	6,44	7,6	5 (RMD)
5	4/5/5/4	4/5/2/3	0,432	5,73	7,16	5,86	5,3	option 4
6	4/5/5/4	3/2/5/4	0,648	5,94	6,3	8,24	6,59	option 1

RMD = popular red meat dish, flexible price assigned depending on CBC design (Table 3A and 3B).

The IACBC is implemented with the methodological toolbox of dise-online (Dynamic Intelligent Survey Engine) [26]. The choice-design of the attribute levels creates unique sets and ensures regular price changes (flexible price component) between each set to capture preferences between substitution options (Table 4).

Variables

The consumption of the RMD is controlled for with a frequency scale ranging from never to at least once a week, which has previously been applied to pulses that are not a daily meal component for any consumer [27]. The RMD consumption is needed to assign less weight to consumers currently not consuming the RMD which the upcoming section explains. Other explanatory variables complement the utility function to better understand the type of consumer with preferences for a specific form of substitution. The analysis can point out consumers more or less willing to accept a specific substitute. We intend to explore the relationship with the following food related characteristics: a. Beef-eating habits, b. Experience with the substitutes, c. Attitude towards out-of-home dining, d. Convenience factor in lunch settings, e. Attitude towards the red meat dishes, f. Price sensitivity and g. Socio-demographics.

The measurement of these concepts is summarized in Table 6 and resemble previous applications. For example, attitude towards out of home dining will be operationalized with the following items, “Going out for lunch is regularly part of my eating habits” and “I do not consider it luxury to go out to have lunch in a restaurant”, which have been introduced within the food related lifestyle concepts by Grunert et al. [28]. The concept allows to control for general preferences with respect to out of home consumption, the scenario consumers are exposed to.

Table 6

Consumer characteristics.

Concept	Base concept	Items	Scale
a. beef eating habits	The frequency scale is abstracted from [27]	The items ask for specific beef products to support participants memory of common beef product when evaluating their own consumption. The frequency for the following consumption items is addressed:• Minced beef• Beef Burger• Beef steak• Beef rips• Beef ham• Beef salami• Any beef	1 = never2 = less than once a year3 = a few times a year4 = Once a month5 = two or three times a month6 = at least once a week
b. Experience with substitutes	Abstracted from Experience with product category [29]	Product category is a placeholder for each of the substitute dishes: I would have described myself as being very familiar with this product category:• Lentil Bolognese• Soy based minced meat Bolognese• Spaghetti Napoli• Vegan sausage• Sliced Emmentaler cheese• Soy based meat balls• Falafel	1 (definitely disagree) to 5 (definitely agree)
c. Attitude towards out-of-home dining	Abstracted from Food related lifestyle scale [28]	The following items are applied• Going out for lunch is regularly part of my eating habits• I do not consider it luxury to go out to have lunch in a restaurant	1 (completely disagree) to 7 (completely agree),
d. Convenience factor in lunch settings	Abstracted from convenience orientation [30]	• It is important to me that I receive my lunch in a reasonable time span• It is important to me that the lunch options are simple to select	1 (definitely disagree) to 5 (definitely agree)
e. Attitude towards red meat dish	Abstracted from Attitude towards Food product [31]	All red meat dishes are evaluated concerning three attitudes towards the dish:• Taste• Socially appropriate• expensive	Semantic differentials 5 point scale:Tastes bad–tastes goodNot socially–sociallyInexpensive—Expensive
f. Price sensitivity	Abstracted from price sensitivity scale [32]	Respondents were asked to “think of the out-of-home purchase situation and rate their agreement with 3 items:• I am willing to make an extra effort to find a low price for a meal• I will change what I had planned to buy in oder to take advantage of a lower price for a meal• I am sensitive to differences in price	1(completely disagree) to 7 (completely agree)

Data analysis

The IACBC is consistent with random utility theory [33]. Consumer “n” derives utility from the choice alternative “a” in a given choice set “t”. We apply a random parameter logit model, similar to Van Loo, Caputo, and Lusk [17] analysis of preferences for lab grown and plant based beef. The following utility function will be estimated: where, μa is an alternative specific constant indicating utility derived from dish “a” relative to the red meat dish (baseline). βn are random parameters for the marginal utility derived from xnat, a vector for price, waiting time, and the CO2-footprint. This allows for consumer heterogeneity with respect to preferences, i.e. how consumers value a price penalty or a reduced waiting time. If the model cannot converge, waiting time, CO2-footprint, and if needed price, can be estimated as fixed parameters. δa are fixed, alternative-specific coefficients on zit, a vector of case-specific variables (income, gender, experience with substitutes, etc.) that describes consumer characteristics associated with preferences for each dish. ǫiat is a random or unobservable term that follows a type I extreme value distribution. The probability that consumer “n” chooses alternative “a” in choice set “t”, conditional on the random parameters, can be written:

From the probability model, the utility for each dish will be calculated. Further, consumers are questioned on the frequency they consume the reference dish, i.e. the popular red meat dish. The response will be used for a subgroup analysis or rather to increase the weight of consumers that heavily consume the red meat dish. The weighting mechanism leads to a second model specification that better accounts for the preferences of consumers that can actually substitute. In a nutshell, the model (1) estimates the utility explained by substitution choices and consumer characteristics based on Eq 1. Model (2) repeats the estimation while weighting consumers by how often they eat the red meat dish. For both models, we will show the marginal effect sizes, p-values, not just the threshold level, and confidence intervals. A postestimation test for seemingly unrelated regressions can further indicate significant differences for coefficients between model specification 1 and 2.

In case of low discriminatory power between the utility derived from the substitutes, i.e. similar WTP for each substitution pathway, a latent class regression approach can be applied to understand the heterogeneity between consumer clusters.

Limitations

When working with stated preferences, it should be acknowledged that food choices are not necessarily conscious decisions. Stated preferences suffer from contextual biases. However, a rational endorsement in a stated preference scenario can be expected to lead to less resistance towards the substitute during food intervention scenarios. Observed and stated preferences are known to correlate. The explored choice tasks do not account for substitution behaviour between different types of cuisines. Consumers may feel like Spaghetti Bolognese, but are swayed by the price of an unrelated substitute, e.g. a salad. The full complexity of food decision making cannot be simulated. The relationship between consumer characteristics and the WTP for substitution options will be pointed out but should not be interpreted as causal inference. A causal analysis of consumer characteristics is limited through the study properties of cross-sectional survey data. Prices, waiting time, and CO2-footprint are manipulated between participants and choice set to allow for causal conclusions.

25 Feb 2021

PONE-D-20-36544

Meatballs, Bolognese and Sausage-buns – the price penalty for red meat substitutes in popular dishes

PLOS ONE

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We look forward to receiving your revised manuscript.

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Damian Adams

Academic Editor

PLOS ONE

Additional Editor Comments:

Thank you very much for submitting your paper to PLOS ONE. Two qualified experts have reviewed your paper, and were supportive of its focus, but identified several concerns that would need to be addressed before the paper could be published. In my opinion, both reviewers provide thoughtful suggestions, which should be fully addressed. Please be sure to carefully and clearly indicate how you have treated each of the comments in your response, and be sure that your revised manuscript fully reflects the needed edits. Thank you,

Damian Adams

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

The research question outlined is expected to address a valid academic problem or topic and contribute to the base of knowledge in the field.

Reviewer #1: Partly

Reviewer #2: Partly

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2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses?

The manuscript should describe the methods in sufficient detail to prevent undisclosed flexibility in the experimental procedure or analysis pipeline, including sufficient outcome-neutral conditions (e.g. necessary controls, absence of floor or ceiling effects) to test the proposed hypotheses and a statistical power analysis where applicable. As there may be aspects of the methodology and analysis which can only be refined once the work is undertaken, authors should outline potential assumptions and explicitly describe what aspects of the proposed analyses, if any, are exploratory.

Reviewer #1: Partly

Reviewer #2: Partly

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3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception, at the time of publication. The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

(Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The paper was presented as Registered Report Protocol and discusses the research design, methodology and its implementation for estimating the price penalty (defined as willingness to pay) for replacing red meat dishes. In particular, the element that seems to lead the author to investigate the willingness to pay for the replacement of the Western diet is the high environmental impact and unhealthiness of a diet heavily skewed towards red meat consumption. In this regard, in the introduction, the author underlines the lack of evidence in the scientific literature regarding the trade-off that consumers face when asked to change their eating habits.

The study is therefore part of a series of sustainable consumption models, and seeks to highlight a critical aspect that has received far too little attention from the scientific community seeking to propose new models of sustainable production and consumption: the consumer and his habits.

The author assumes that consumers are willing to substitute the meat dishes they normally consume in return for a price penalty (lower willingness to pay) and this is fundamentally acceptable given that the target of the research also aims to highlight the willingness to pay on the part of frequent red meat consumers, therefore with very well rooted eating habits.

My main concern is how the environmental aspect was considered in the study. In fact, the author states that "The research objectives are complemented by exploratory research on the relationship of consumer characteristics with a preference for a substitution option and a calculation of what CO2 taxing level would flip the preference structure if any". The environmental aspect, which was heavily emphasised in the introduction of the work, takes a back seat and becomes a complementary element. This also emerges in the paragraph on the definition of attributes, where the author states that the choice set includes only three attributes: dish, price and waiting time.

Certainly the dish must be one of the attributes, just as the price is essential in determining willingness to pay. However, the choice of the third attribute, waiting time, even if as the author states "represents the value of time which matters particularly in lunch settings and hints at a convenience factor of interest to all kinds of food interventions" should be evaluated more thoroughly.

In my opinion, given that the whole study is designed to assess the link between sustainable consumption patterns and consumer willingness to adopt them, one of the three attributes (if the author does not consider it appropriate to add a fourth) should clearly emphasise the environmental qualities of the substitute dishes, otherwise the consumer's choice of preferred combination of attributes is completely disconnected from the environmental and health characteristics on the basis of which the need to replace the use of red meat in dishes arises.

This aspect, highlighted by the author in Table 1, should be clearly explained to the consumer. In the paragraph on the choice procedure, it is stated that the dishes are explained neutral, however it should be pointed out which aspect of the dishes was explained: only the main ingredients or also the related CF data? I know this may seem like a quibble but it isn't because it would place the study clearly and unequivocally in the context in which the author stated he wanted to place the study from the very first lines of the introduction.

In this same vein, the author should better explain how he wants to relate the results of the IACBC to those of the Carbon Footprint calculation and thus the carbon tax. How might these relationships affect the preference structure and why?

The paragraphs on Sampling procedure, Choice procedure, IACBC and data analysis are well structured, clear and provide the reader with all the necessary information to understand how the methodology under study will be implemented.

As a suggestion for the improvement of the study I suggest the author to better investigate the scientific literature on the application of LCA methodology to different diets, because the studies cited are a bit 'dated and much has been published in this direction by the scientific community.

Reviewer #2: The paper discusses consumer preferences on the substitution of red meat used in the preparation of different food receipts. Despite the interest of the topic, the paper suffers from severe limitations because it does not represent a complete analysis and is lacking from results.

1 title The authors should rethink about the title; maybe better not to mention the examples (red-meat dishes) and just highlight their focus on red meat. However, this is only a personal idea (that does not mean they should do it).

2 Introduction Globally, the introduction should be restructured and rephrased.

3 line 25 the first sentence can be better explained and referenced; alternatively, it should be better to remove it.

4 lines 25-33 better to rephrase, highlighting more who says what (references).

5 lines 25-42 From the beginning, the authors should clearly state and justify their focus on Germany.

6 lines 49-50 "Consumer choices, however, occur on a dish or ingredient level, since the majority of consumers is not committed to a specific diet." Are the authors sure of what they mention? Can they provide a reference for this statement? Honestly, I am not sure this is true (e.g. think about the Mediterranean diet). This cannot be generalised. The authors should better specify it with a reference.

7 line 56 "Additionally, in line with a review by Boer and Aiking (3), this study accounts for the multitude of options to substitute". At the end of this sentence, I would ask: "to do what?". I mean that the authors here introduce this sentence to only partially explain what they will do (within the research). I think the aim should be better and clearly stated.

8 lines 56-60 Where do these options come from? A previous focus group? An existing study? It should be explained to justify them.

9 line 60 Here, the authors mention Spaghetti Bolognese for the first time, without explaining why they mention this. It is not clear for the reader why.

10 lines 60-63 The same of comment n. 8 (please, see above)

11 line 67 Please, remove "I"

12 lines 67-68 This should proceed with what stated in lines 56-63.

13 Theoretical background: I wonder why these four substitutes are being applied to the German sample. Are there any similar studies, before this, dealing with a similar topic on this sample, showing the existing of a knowledge gap that this study could/might fill? I have the idea that the choice of the sample is not justified at all. Moreover, the paragraph globally should be revised, improved both with literature and own description of what the authors are presenting.

14 lines 77-79 Please, improve this part with a more in-depth literature analysis on consumer behaviour on substitution preferences (see your statement: line 54). This is important before starting to describe the four types of substitutes you consider in your study.

15 line 111 Please, get rid of "I". Moreover, what is the role of "whether" in that sentence?

16 line 112 I think the authors mean the four substitutes ("for each dish"). As the authors previously stated, CO2 footprints are based on estimations by IFEU-institute. So, what have the authors done here? Just compared the CO2 footprints of Spaghetti Bolognese, beef topping for 2 buns with butter, and beef meatballs with rice and peas with the relative 4 substitutes? Or have they previously measured the CO2 footprints for the substitutes, before comparing these with that retrieved from IFEU. This is not clear to me.

17 Research objective In this paragraph, the authors state their hypothesis but these are not supported by any relevant previous reference in the literature. It seems to me that such a kind of analysis is a bit self-referential, probably it does not fit the scope of a scientific publication at all.

18 lines 122-123 "Empirical evidence on the WTP for substitution pathways is scarce". I suggest the authors use this statement also within the previous paragraph, to help them explain why they are doing this kind of research.

19 line 124 Please, get rid of "I".

20 Study design: The last part of this paragraph should be stated previously, to justify the research (e.g. describing possible implication, although very briefly).

21 Variables: In this paragraph, the authors should explain all the variables they mention to consider in their research (explanation is provided only for out-of-home consumption habits and consumption habits). Moreover, a table would be used to report all the items and scales. Moreover, the scale mentioned in line 159 should be the opposite (or did the authors reverse the scale? In this case, it should be explained). This paragraph does not provide enough information and should be deeply improved.

22 line 148 Please, get rid of "I".

23 lines 185-200 The authors should clearly state why they chose those three attributes (e.g. inspired by any relevant paper?). Moreover, both the attributes and their levels should be included in a table: this could make it easier for the reader to understand.

24 Results and conclusions are missing in the paper.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

22 Mar 2021

Please refer to the formatted response at the end of the PDF-file

Submitted filename: Respone to Reviewers.docx

Click here for additional data file.

20 May 2021

The price penalty for red meat substitutes in popular dishes and the diversity in substitution

PONE-D-20-36544R1

Dear Dr. Lemken,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Damian Adams

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Thank you very much for submitting your revised protocol. Based on reviewer comments, I am happy to accept the protocol at this stage.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

The research question outlined is expected to address a valid academic problem or topic and contribute to the base of knowledge in the field.

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses?

The manuscript should describe the methods in sufficient detail to prevent undisclosed flexibility in the experimental procedure or analysis pipeline, including sufficient outcome-neutral conditions (e.g. necessary controls, absence of floor or ceiling effects) to test the proposed hypotheses and a statistical power analysis where applicable. As there may be aspects of the methodology and analysis which can only be refined once the work is undertaken, authors should outline potential assumptions and explicitly describe what aspects of the proposed analyses, if any, are exploratory.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception, at the time of publication. The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

(Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors carried out a thorough and valuable revision of the paper. All the critical issues that emerged from the analysis of the first version of the paper have been resolved and the paper is now ready for publication in PLOS ONE. I suggest the authors to make a careful analysis of all the text, tables and figures to correct any typos that become difficult to detect in track change mode.

Reviewer #2: The author/s improved the paper answering point to point to all the comments.

I am satisfied with current version of the paper.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

25 May 2021

PONE-D-20-36544R1

The price penalty for red meat substitutes in popular dishes and the diversity in substitution

Dear Dr. Lemken:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Damian Adams

Academic Editor

PLOS ONE