An exploration of customers’ perceptions, preferences, experiences, and feasibility of offering standardized portions in restaurants

Abstract

Excess caloric intake increases the risk of weight gain, and diet-related chronic diseases. Restaurants play an integral role in the portions of food people consume. Standardization of portion sizes in restaurants can help customers recognize appropriate portions. Through customer interviews, we aimed to assess and understand the feasibility, perceptions, and acceptability of standardized portions in restaurants. Kaiser Permanente partnered with three restaurants in Southern California to create alternative menu options of meals that would not exceed 700 calories. Kaiser Permanente members who lived within a 5-mile radius of the restaurants were informed through email about the study. Customers (N=33), who dined at one of the restaurants participated in a one-on-one semi-structured interview. Interviews were recorded, typed, transcribed verbatim, and analyzed using thematic analysis. Four themes emerged from the analysis: 1) Customers perceive standard portions as a better choice and the benefits outweigh regular portions; 2) Individual and restaurant-related factors may influence portion preferences; 3) Restaurant portions are perceived to be in excess of what customers need; and 4) Portion standardization is an evolving area for restaurants. Our findings suggest positive perceptions and acceptance of standardized portions among restaurant customers. Customer awareness and restaurant standardization procedures can improve customers’ dining experience.

1. Introduction

Excess caloric intake is a major contributor of obesity, a risk factor for diet-related chronic diseases and a leading cause of death and disability globally (Camacho and Ruppel, 2017; Collaborators, 2019). Weight loss interventions and strategies have been extensively documented in the literature (Madigan et al., 2022; Myers-Ingram et al., 2023; Twells et al., 2021), yet no population-level decline in obesity prevalence has occurred. For instance, the United States (U.S.) adult obesity prevalence increased from 30.5% in 2000 to 41.9% in 2020 (Prevention, 2022). This rate is projected to increase to about half of the U.S. adult population by 2030 (Ward et al., 2019).

Physical activity effectiveness in reducing the risk of diet-related disease and weight loss has also been well established and documented (Madigan et al., 2022; Myers-Ingram et al., 2023; Twells et al., 2021). However, the United States Physical Activity Guidelines for Americans emphasizes that both physical activity and caloric intake must be considered to control body weight (U.S. Department of Health and Human Services, 2018). As a result, researchers recommend portion control for sustained body weight management and optimal health benefits (Rolls, 2014). Furthermore, previous studies provide evidence of associations between excessive caloric intake, higher portion sizes, and dining out (Gesteiro et al., 2022; Kim and Ahn, 2020).

Restaurants play a fundamental role in the amount of food we consume (Cohen and Story, 2014). In addition, the availability of online menus and food delivery services have contributed to increases in commercially prepared food purchases over the years (Brewer and Sebby, 2021). According to a 2022 report by the United States Department of Agriculture (USDA), food-away-from-home spending accounted for 56% of all total food expenditures in the U.S. (U.S. Food and Agriculture, 2023). Compared to homemade meals, commercially prepared foods are of poorer nutritional quality (Gesteiro et al., 2022) and are calorically dense with higher amounts of sodium, fat, and added sugars (Rehm and Drewnowski, 2016). Studies on portion sizes document that restaurant servings surpass the USDA recommended caloric intakes (Nielsen and Popkin, 2003; Smiciklas-Wright et al., 2003; Young and Nestle, 2002). The lack of customers’ ability to control restaurants regular portions may contribute to overconsumption (Cohen and Story, 2014). As a consequence, when people cannot control the amount of food served in commercial places, they consume more than they need, (Rolls, 2014).

Clearly, there is a need for standardized portions in the food environment and to increase awareness of the risk excessive caloric intake poses to our health (Cohen and Story, 2014). Thus, we conducted a pilot study on standardized portions in three Southern California restaurants. This study aimed to assess and understand the feasibility, perceptions, and acceptability of standardized portions in restaurants through customer interviews.

2. Methodology

We explored restaurants adherence to standard portions, customers’ preference for standard portions, and assessed the effectiveness of standardized portions on caloric intake. We partnered with the restaurants to create an alternative menu based on standardized portion sizes, in addition to their regular menu. All alternative menus, which we refer to as standard portions menus were developed by a dietitian/nutrition expert. The standard portions were the same as regular menus except that they were portioned so that a complete meal would not exceed 700 calories. In developing the standard portions, we limited calories of appetizers to 150, plain entrees to 200 calories, sides to 100–150 calories, and mixed entrees to 350 calories, beverages to 100 calories and desserts to 100 calories. Portions were limited so that the quantity served would not exceed these guidelines (see Table 1).

Table 1:

Examples of meals offered in standard portions

Items	Quantity	Calories	Total calories
Sample two
Burger/bun	3 oz meat, burger, ketchup	450	700
Fries	1.75 oz	150
Milk 1%	8 oz	100
Sample two
Salad	2 tablespoon dressing	150	625
Spaghetti	6 oz	150
Meatballs/sauce	3 oz	200
Broccoli	1 cup	35
Cheesecake	1 oz	90
Water	8 oz	0
Sample three
Chicken Fajitas	3 oz	200	645
Tortillas (corn)	2	120
Rice	6 oz	150
Beans	6 oz	150
Zucchini	1 cup	25
Water	8 oz	0

2.1. Design and setting

The Standard Portions study was piloted in three Southern California restaurants. Kaiser Permanente members who lived within a 5-mile radius of the restaurants were informed through email and text about the study. Interested Kaiser Permanante members visited the restaurants within the study timeframe and ordered either from the restaurant’s standard portion or regular menu. We defined standard portion as a menu item or meal ≤700 calories (see Table 1 for examples). Restaurants were allowed to decide the price of their standard menu and whether they wanted to offer standard portions alone or plate and serve the meal from the regular menu to conform with the standard portions guidelines and pack the leftovers to go.

Next, we qualitatively assessed customers’ perceptions, acceptability, and feasibility through interviews. However, during the interviews we referred to standard portions as “Balanced portions”. We asked both standard and regular portion adult customers (N= 33) who dined at participating restaurants to complete a 10 to 15-minute one-on-one semi-structured interview (see Table 2) in person or over the phone between October 2022 and May 2023.

Table 2:

Main topics covered during semi-structured interviews and examples of questions asked

Topics covered	Example of questions
Overall perception of standard portion	What was your impression of the alternative menu?
Motivating factors/facilitators	• What was the primary reason for ordering from the alternative menu?
Opinion regarding value, and quantity	• How did you feel about being offered to have the remainder of your meal packaged for leftovers?
Evaluating excess portioning by restaurants	Did you take any leftover food in a to-go bag from your visit at the restaurant?
Recommendations for standardized portions	What suggestions do you have regarding how the alternative menu could have been designed to be more eye-catching/appealing?

2.2. Sampling

Participants were selected who purchased food at the participating restaurants. These individuals were selected based on their availability after dining at the restaurants and ability to share perspectives and feedback about standard portions. The research staff followed up with potential participants through phone calls after they had purchased a meal at the restaurant or approached diners at the restaurants. Participants were interviewed regardless of the type of menu purchased (that is, standard or regular menu).

2.3. Data analysis

Interviews were audio recorded, transcribed verbatim and typed into a document by the interviewer. Research staff reviewed and analyzed interview transcripts and notes using thematic analysis. This approach allowed us to identify themes and convergent or divergent perceptions of portion standardization among participants (Braun and Clarke, 2006).

Using Dedoose software (version 9.0.90) (Dedoose, 2023), experienced qualitative research staff created codebooks that included several short words (codes). Next, similar codes were categorized and grouped into themes based on their interconnectedness. The emergent themes were supported with direct quotes from participants. Overall, four themes emerged from the qualitative data analysis as described below.

3. Results

Thirty-three customers from the three restaurants completed a semi-structured one-on-one interview in person or over the phone. The characteristics of the participants who ordered from the standard and regular menus are shown in Table 3. Among those interviewed, slightly over half (55%) were females, 49% were at least 50 years old, and 36% identified as Hispanic. Fifty-six percent of the interviewees ordered from the standard portion menu and were more likely to identify as White males above 50 years old.

Table 3:

Characteristics of participants who completed semi-structured one-on-one interviews

Characteristics	Total participants interviewed N (%) (N = 33)	Ordered from standard portion menu N (%) (N = 18)	Did not order from standard portion menu N (%) (N = 15)
Gender
Female	18 (54.5)	8 (44.4)	10 (66.7)
Male	15 (45.5)	10 (55.6)	5 (33.3)
Race/Ethnicity
African American or Black	2 (6.1)	1 (5.5)	1 (6.7)
Asian	3 (9.1)	1 (5.5)	2 (13.3)
Native American	2 (6.1)	-	2 (13.3)
White	11 (33.3)	9 (50.0)	2 (13.3)
Hispanic/Latino	12 (36.4)	5 (27.8))	7 (46.7)
Other	3 (9.1)	2 (11.1))	2 (13.3)
Age
18 to 25 years	6 (18.2)	3 (16.7)	3 (20.0)
26 to 50 years	9 (27.3)	4 (22.2)	5 (33.3)
Above 50 years	16 (48.5)	10 (55.6)	6 (40.0)
Not reported	2 (6.1)	1 (5.5)	1 (6.7)

3.1. Customers perceive standard portions as a better choice and the benefits outweigh regular portions

Participants had several perceptions about standard portions. Interestingly, both standard and regular portion diners mostly agreed that the availability of standardized portion menus will not take away what they enjoy eating but offer the opportunity to make healthy food-choice decisions. Participants described standard portions as appealing and simplified alternatives to the regular menu. Some participants shared that the standard portions could help them narrow their choices and gain control over what they wanted to be portioned versus what they must get. However, a few participants who already had their favorite or predetermined menu did not think standard portions were better choices.

When asked about their impression of the standard portion, one participant who ordered from the standard portion said:

“It didn’t seem like it was something different than what they ordinarily would serve. It seemed it was possibly a smaller portion than what you would normally get. It was nicely put together in a box that you could either eat or take away.”

A customer who ordered from the regular menu because they ate in a group, described their impression and perceived benefits of standard portions:

“The concept reminds me a lot of a Bento box- I like that there are vegetables in it. I like the variety I receive in a Bento box, so a similar dish will interest me. What I like about the balanced portion menu is that I do not have to do any mental work in ordering. You’ve done all of the homework, and now I just order a balanced dish with the vegetables I want in my next meal.”

We also noticed that regardless of the type of menu ordered, nearly all the participants agreed that standard portions were healthier and may promote optimal diet and eating habits.

Here is how a participant who purchased a meal from the standard portion menu described how standard portions can help them optimize their dietary needs:

“I struggle to get a variety of vegetables, and I live in a senior community. I have an option of dining on-site. The vegetables are just not appealing to me. So, going out and finding dishes with vegetables that are fresh and not frozen is what I like. A balanced dish like the one I had was great, and I hope to see more menus like this one.”

While this participant did not order from the standard portion menu, they acknowledged that it is a healthy choice:

“If you want simple food, you have a choice of something healthy with the balanced portion menu.”

Similarly, another participant who ordered from the regular portion menu described how standard portions could help them control their portions.

“I already portion control my dishes, and this would be very convenient. I used to do Weight Watchers, and this option would be so convenient and the work would be done for me”.

3.2. Individual and restaurant-related factors may influence portion preferences

Participants shared multiple factors they may consider when placing an order and deciding on portion menus. In particular, participants identified cost, value, quantity, restaurant type (for example, Asian versus American), and available menu options as important factors. Overall, opinions regarding quantity and cost were mixed among participants. While some participants thought the standard portion cost was commensurate with the regular menu, others indicated that standard portion menus were more expensive. However, it appeared that the value of food served might have the strongest influence on participants’ decisions.

We noticed a pattern regarding cost in one of the three restaurants. Most of the participants who expressed concerns regarding cost or thought standard portions were more expensive dined at the same restaurant. Here is what a participant who ordered from the regular portion menu and who thought cost would be a major factor in their decision said:

“I would like the different options. I just don’t want less food for more money.”

One participant who ordered from the regular portion menu and would pick value over size said:

“The portion sizes are important to me, but I also look for the value. If the full-sized portion is a better value that’ll give you two or three meals, I’ll do that then.”

In contrast, a participant who opted for the standard portion menu thought they got more for what they paid. For this participant, they had the standard portion served to them at the restaurant and went home with the additional portion they would have gotten from a regular portion menu:

“It feels like you’re getting two meals for the price of one. It’s the same price, why not?”

Surprisingly, participants did not mention body weight or health conditions as factors that could influence their preference for standard portions.

For this participant who ordered from the standard portion menu, they said:

“I’m more on the slim side, and my own lifestyle has kept me from gaining weight so I have no problem with dividing the portion.”

A few participants shared challenges they might face when deciding menu options or dining at specific restaurants. For instance, participants described that even if standard portions were made available at certain restaurants, such as Asian and Latin restaurants, opting for regular portions might be tempting for people trying to eat healthy as they offer affordable menu items. For example, one participant who ordered from the standard portion menu said:

“I think with Chinese food it’s like a huge dish, so it’s hard to use self-control.”

Another participant who ordered from the standard menu expressed some of the challenges they faced at some restaurants.

“I’m always looking for smaller portions and healthier choices. Sometimes with Chinese food, unless you are ordering a lot of vegetables. I don’t always find that.”

3.3. Restaurant portions are perceived to be in excess of what customers need

Participants described the portions served by the restaurants regardless of the type of menu they ordered. In particular, participants discussed how the portions exceeded their calorie needs and shared how excesses or leftovers were managed. For instance, those who ordered from the regular menu mentioned sharing with family members or eating leftovers at a later time as ways they managed excess portions. There was a consensus among most of the participants that the regular portions exceeded their dietary needs. Most customers who ordered from the standard portion agreed that the portions were suitable for their dietary needs. Even with standard portions, a few participants still felt they got more than needed, portion-wise.

During an interview with a participant who ordered from the regular menu, they described how much leftovers they had.

“We had enough leftovers for at least one to two more meals. On the first day, two meals and on the second day, one meal. I think we supplemented with a salad or some other things with it.”

Another participant who ordered from the regular portion admitted that their portion was “a lot.”

“I had to take food home from the regular menu; it was a lot.”

Interestingly a participant who ordered from the standard menu still thought they received “a huge portion.”

“I did end up having enough for a meal. I ended up giving it to my mom, actually. It was a huge portion.”

For this participant who ordered from the standard portion, they described how the standard portion helped them eliminate the stress of handling leftovers.

“Normally we were taking home leftovers because I usually split the meal up in two anyways. It [balanced portion] was kind of the perfect size, so I didn’t have to do that.”

3.4. Portion standardization is an evolving area for restaurants

Finally, participants shared various ways to increase awareness, acceptance, adoption among restaurants and improve portion standardizations. Recommendations did not differ by the type of menu the customers ordered. However, participants who ordered from the standard menu were able to share their experiences and recommendations for restaurants. For example, those who ordered from the standard portions suggested that instead of restaurants serving standard portion and pack the remaining for the same price of regular menu, they should offer standard portions alone for a lower price. About half of the participants who ordered from the regular menu mentioned either not noticing or were not offered the standard portion menu option by the restaurant, and they might have opted for standard portions instead. As a result, more than half of the participants who ordered from the regular menus emphasized the need to enhance visuals and increase awareness of standardized portions and health benefits.

For this participant, they did not order from the standard portion because they were not offered:

“If there was a separate menu, we didn’t see it. If there was an alternative menu, I didn’t know, they never offered it to us.”

While another participants who also did not order from the standard menu recommended emphasis on pictures over text; For example, one participant said:

“If it is laid out in front of you, this is what a portion is, people start to think that way. A piece of meat should be the size of your palm, rice should be a ½ cup of rice. Reading it and seeing it visually is very different.”

In the same vein, this participant, who ordered from the regular menu, thought visuals with less text were also crucial for promoting standard portions:

“Make the pictures bigger, especially if you want to highlight this on the menu. Remove the small text describing the food. No need to have so much text on the ingredients; these details are not important for me. Make the heading of the food choices bigger.”

Even though this participant ordered from the standard portion, they also emphasized on visuals, consensus, and awareness about standard portions said:

“It needs to be catchy like Fit N Healthy, and they[restaurants] need to look for the same logo. I’m big on logo titles. The balanced portion menu did not catch my attention.”

In addition, participants who ordered from the standard portion menu recommended eliminating some steps. For example, one participant had this to say:

“Possibly if the meals were smaller and the price was lower, maybe like $11.95 served at lunch or something. It might work well for people who want something for lunch and do not want leftovers because they have to carry it back to the office, put their name on it, more trouble than it’s worth, they are not looking to take leftovers, they just want to eat and move on.”

Another customer who ordered from the standard portion suggested that offering portion sizes alone rather than portioning a regular menu into standard portion and to-go boxes may be more attractive to diners:

“It [the menu] had pictures which is good. I think the menu layout was fine. Maybe the best would be to offer the half portion at half price, gives customers more options.”

4. Discussion

Through one-on-one interviews, we sought to explore the feasibility, perceptions, preferences, and experiences with standard portions among restaurant customers who participated in the Standard Portions study. Customers recognized the importance of portion standardization, particularly as it relates to their dietary needs when dining out. However, restaurant and customer-related factors may influence portion choices. This paper offers customers’ experiences and perspectives on standardized and regular portions served at three restaurants in Southern California. The one-on-one participants’ interviews allowed participants to share their perceptions, experiences, and recommendations for standardized portions. Study participants, regardless of the menu ordered, agreed that the benefits of standardized portions, including the ability to optimize dietary needs and make healthy choices, outweigh benefits derived from regular options such as quantity. This theme supports previous studies that highlighted and described the role of standardized portions in diet-related disease prevention (Cohen and Story, 2014; Langfield et al., 2023; Poelman et al., 2016). For instance, in a study of high-income countries with varied packaged commercial food and beverages, customers considered the product’s healthiness when opting for sizes (Poelman et al., 2016). According to Zuraikat and colleagues (Zuraikat et al., 2019), multi-level factors, including environment, the food itself, and individual factors, moderate the effects of portion sizes. The researchers found that the value customers derive from food reduces portion size effect, which corroborates our finding (Zuraikat et al., 2019). Furthermore, our interviews with participants suggest that customers would like to eat healthy regardless of body weight. Those who considered themselves normal weight wanted to stay healthy and opted for standard portions, while those who reported trying to lose weight thought standardized portions might help them achieve their goals.

While most of our participants acknowledged the benefits of standardized portions, about a third had reservations and expressed their concerns. In addition, barriers to standard portions were also discussed by a few participants. Interestingly, participants expressed mixed feelings regarding the cost of standard portions. Some participants who ordered from the standard portions thought the cost of their food was commensurate with the portion served, while a few thought they received less than what they paid for. Our interviews with participants revealed patterns in participants’ responses. Participants who shared their concerns about cost were mostly from one of the three restaurants, implying that restaurant-related factors might have contributed to participants’ experiences. In a quasi-experimental study on restaurant food cost and portion changes (Ge et al., 2018), customers’ perceived cost of food was dependent on the food quality and intention for purchase which could be the reason for mixed findings among customers. Although we did not ask participants for their body weight during the interview, our findings support Vermeer and colleagues’ (Vermeer et al., 2009) study on the impact of proportion-sized prices on customers’ choices. These researchers found that fast-food customers who were overweight were more likely to opt for smaller portions with reduced prices (Vermeer et al., 2009).

Restaurant portions are perceived to be in excess of what customers need was a strong theme that appeared in more than two-thirds of the interviews regardless of the type of menu or portions participants purchased. Overall, most of our participants agreed that regular portions provided by restaurants may be too much for a meal. However, opinions regarding portion sizes among regular portion diners were mixed. While some regular portion diners thought the portions they received exceeded their dietary needs, others did not mind since they could share with others or eat the leftovers later. In fact, more than half of the participants who ordered from the regular menus had plans for leftovers. We did not specifically ask participants what they did with the leftovers, but some voluntarily mentioned consuming them. Our findings corroborate Talwar et al (Talwar et al., 2021) that customers with favorable attitudes toward taking leftovers home when they dine out were less likely to throw them away.

Overall, participants had positive perceptions towards standard portions regardless of the type of menu they purchased and offered recommendations for promotion and scalability. A consensus that standardized portions is an evolving area was a strong theme across all interviews, This aligns with what have been previously reported by researchers that transitioning to new food standards may take time and would involve training staff and access to needed resources for implementation (Cohen and Story, 2014; Steenhuis and Vermeer, 2009). Our study participants offered several recommendations that could simplify commercial food standardization and potentially appeal to customers. Some of these suggestions were primarily related to pricing and portioning. For instance, two of the restaurants we recruited offered standardized portions at their regular prices but served standard portions for customers who dined in and packaged the excess. Participants recommended that eliminating the extra packaging process may improve logistics, reduce prices, and appeal to customers interested in standard portions. According to a Los Angeles County Department of Public Health countywide study on restaurant owners’ perspective of reduced sizes (Gase et al., 2014), logistic barriers such as the need for smaller serving vessels or the availability of smaller food items (e.g., tortillas, hot dogs) hindered offering reduced-size portions for some menus. None of the restaurants in this study were willing to reduce prices on the standard portions menu as they did not want to lose any profits.

4.1. Limitations

A lack of generalizability limits the findings of this study as data only included participants from three restaurants within a region. In addition, customers ordered from three different restaurants that offered varied food choices. Furthermore, we did not factor in differences in restaurant types which could have influenced customers’ overall experience, perception, or preference for standard portions. We purposefully recruited three restaurants to understand the feasibility of delivering standardized portions in different settings. Finally, to limit the amount of personal information collected, we did not collect specific data such as body weight and food security status, which could have contributed to participants’ responses during the interviews.

5. Conclusion

Overconsumption or excessive caloric intake increases the risk of diet-related and chronic disease conditions. Restaurants play a central role in the portions of food people consume when they dine out. The results of this pilot study provide information on how customers perceive portion standardization, the feasibility of offering standardized portions to customers and potential ways restaurants can optimize the process. Standard portions were generally well perceived and accepted by restaurant customers. However, factors such as cost of purchase, customers’ perception of the value of food provided and awareness of standard portions are vital for the adoption and scalability of standard portions in larger and diverse settings. Future studies investigating the health benefit of standardized portions, implementation of standard portions, and cost-effectiveness are recommended.

Highlights.

• Restaurant menus within recommended caloric intakes are deemed better by customers

• Food value, cost, and quantity influence on customers’ portion preferences

• Customers believe restaurant portions exceed their calorie needs

• Restaurants can improve dining experience through standardization of portion sizes

Implication for gastronomy.

Dining out is increasingly popular and the availability of delivery services contribute to increase in commercial food purchase. Restaurants play a major role in how much food customers consume. Further, excessive food consumption increases the risk of diet-related diseases. Thus, creating standard portions and helping customers recognize healthy portions are curial to improved overall health.

This article highlights customers perceptions, experiences, and preference for standard portions at restaurants. It helped to identify customers’ food portion preferences, explained their experiences, and offer recommendations to restaurants and policymakers within the food environment to improve consumer’s experience. Overall, customers would love healthy foods and portions served to them at affordable prices.