The effect of wine glass size on volume of wine sold: a mega-analysis of studies in bars and restaurants.

AIM: To estimate the effects of wine glass size on volume of wine sold in bars and restaurants. DESIGN: A mega-analysis combining raw (as opposed to aggregate-level) data from eight studies conducted in five establishments. A multiple treatment reversal design was used for each data set, with wine glass size changed fortnightly while serving sizes were unaffected, in studies lasting between 14 and 26 weeks. SETTING AND PARTICIPANTS: Five bars and restaurants in England participated in studies between 2015 and 2018, using wine glasses of five sizes: 250, 300, 370, 450 and 510 ml, with the largest size only used in bars. MEASUREMENTS: Daily volume of wine sold by the glass, bottle or carafe for non-sparkling wine were recorded at bars (594 days) and restaurants (427 days), averaging 4 months per study. FINDINGS: Mega-analysis combining data from bars did not find a significant effect of glass size on volume of wine sold compared with 300-ml glasses: the volume of wine sold using 370-ml glasses was 0.5% lower [95% confidence interval (CI) = -8.1% to 6.1%], using 450-ml glasses was 1.0% higher (95% CI = -9.1 to 12.2) and using 510-ml glasses was 0.4% lower (95% CI = -9.4 to 9.4). For restaurants, compared with 300-ml glasses, the volume of wine sold using 250-ml glasses did not show a significant difference: 9.6% lower (95% CI = -19.0 to 0.7). Using 370-ml glasses the volume of wine sold was 7.3% higher (95% CI = 1.5% to 13.5%); no significant effect was found using 450-ml glasses: 0.9% higher (95% CI = -5.5 to 7.7). CONCLUSIONS: The volume of wine sold in restaurants in England may be greater when 370-ml glasses are used compared with 300-ml wine glasses, but may not be in bars. This might be related to restaurants compared with bars selling more wine in bottles and carafes, which require free-pouring.

Understanding price incentives to upsize combination meals at large US fast-food restaurants.

OBJECTIVE: To understand price incentives to upsize combination meals at fast-food restaurants by comparing the calories (i.e. kilocalories; 1 kcal = 4·184 kJ) per dollar of default combination meals (as advertised on the menu) with a higher-calorie version (created using realistic consumer additions and portion-size changes). DESIGN: Combination meals (lunch/dinner: n 258, breakfast: n 68, children's: n 34) and their prices were identified from online menus; corresponding nutrition information for each menu item was obtained from a restaurant nutrition database (MenuStat). Linear models were used to examine the difference in total calories per dollar between default and higher-calorie combination meals, overall and by restaurant. SETTING: Ten large fast-food chain restaurants located in the fifteen most populous US cities in 2017-2018. PARTICIPANTS: None. RESULTS: There were significantly more calories per dollar in higher-calorie v. default combination meals for lunch/dinner (default: 577 kJ (138 kcal)/dollar, higher-calorie: 707 kJ (169 kcal)/dollar, difference: 130 kJ (31 kcal)/dollar, P < 0·001) and breakfast (default: 536 kJ (128 kcal)/dollar, higher-calorie: 607 kJ (145 kcal)/dollar, difference: 71 kJ (17 kcal)/dollar, P = 0·009). Results for children's meals were in the same direction but were not statistically significant (default: 536 kJ (128 kcal)/dollar, higher-calorie: 741 kJ (177 kcal)/dollar, difference: 205 kJ (49 kcal)/dollar, P = 0·053). Across restaurants, the percentage change in calories per dollar for higher-calorie v. default combination meals ranged from 0·1 % (Dunkin' Donuts) to 55·0 % (Subway). CONCLUSIONS: Higher-calorie combination meals in fast-food restaurants offer significantly more calories per dollar compared with default combination meals, suggesting there is a strong financial incentive for consumers to 'upsize' their orders. Future research should test price incentives for lower-calorie options to promote healthier restaurant choices.

Does the cost of a meal influence the portion size effect?

Serving larger portions leads to increased intake, but little is known about how the cost of a meal affects this response. Therefore, we tested whether the amount of money paid for a meal influenced the portion size effect at a lunch served in a controlled restaurant-style setting. In a crossover design, 79 adults (55 women; 24 men) came to the lab once a week for 4 weeks to eat a main dish of pasta with side dishes. Across weeks, the meal was varied in two factors: portion size of the main dish (400 g or 600 g) and cost of the meal (US$8 or $16). At discharge subjects completed questionnaires that assessed behaviors thought to influence the response to portion size and cost. Results showed that the portion size of the main dish had a significant effect on meal intake (P < 0.0001). The weight of food consumed at the meal increased by 18 ±â€¯2% (mean ±â€¯SEM 83 ±â€¯11 g) and energy intake increased by 20 ±â€¯2% (133 ±â€¯16 kcal) when the larger portion was served. These effects of portion size did not differ across the two levels of cost (both interactions P > 0.37) nor did meal cost have significant effects on meal intake (both P > 0.24). Subject scores for satiety responsiveness did, however, influence the effect of portion size on food intake (P = 0.0007). Serving larger portions led to increased intake in subjects with lower satiety responsiveness scores (P < 0.0001), but did not affect intake in those with higher scores. In summary, the effect of portion size on intake in a restaurant-style setting was not influenced by meal cost but was attenuated in individuals higher in satiety responsiveness.

Modelled Cost-Effectiveness of a Package Size Cap and a Kilojoule Reduction Intervention to Reduce Energy Intake from Sugar-Sweetened Beverages in Australia.

Interventions targeting portion size and energy density of food and beverage products have been identified as a promising approach for obesity prevention. This study modelled the potential cost-effectiveness of: a package size cap on single-serve sugar sweetened beverages (SSBs) >375 mL ( package size cap ), and product reformulation to reduce energy content of packaged SSBs ( energy reduction ). The cost-effectiveness of each intervention was modelled for the 2010 Australia population using a multi-state life table Markov model with a lifetime time horizon. Long-term health outcomes were modelled from calculated changes in body mass index to their impact on Health-Adjusted Life Years (HALYs). Intervention costs were estimated from a limited societal perspective. Cost and health outcomes were discounted at 3%. Total intervention costs estimated in AUD 2010 were AUD 210 million. Both interventions resulted in reduced mean body weight ( package size cap : 0.12 kg; energy reduction : 0.23 kg); and HALYs gained ( package size cap : 73,883; energy reduction : 144,621). Cost offsets were estimated at AUD 750.8 million ( package size cap ) and AUD 1.4 billion ( energy reduction ). Cost-effectiveness analyses showed that both interventions were "dominant", and likely to result in long term cost savings and health benefits. A package size cap and kJ reduction of SSBs are likely to offer excellent "value for money" as obesity prevention measures in Australia.

Portion Size: Latest Developments and Interventions.

PURPOSE OF REVIEW: The aim of this review is to provide an overview of (1) underlying mechanisms of the effect of portion size on energy intake, (2) external factors explaining the portion size effect and (3) interventions and measurements aimed at food portion size. RECENT FINDINGS: Previous studies have shown that portion sizes have increased in recent decades. Many experimental studies have been conducted to unravel the mechanisms underlying the portion-size effect on food intake (e.g. the appropriateness mechanism, the 'unit bias' mechanism, the 'previous experience/expectation' mechanism, the 'visual cue' mechanism and the 'bite size' mechanism). In addition, external factors have been found to drive food portion selection and consumption (e.g. value for money, mindless eating, levels of awareness, estimation bias. Research on several interventions (ranging from 'providing information' to 'eliminating choice') have been conducted, but remain scarce, especially intervention studies in which portion size is a key focus in weight loss. Moreover, only three new instruments with respect to portion control behavior have been developed. There is considerable evidence for the portion-size effect on energy intake. However, the work on interventions targeting portion size and measurements for portion control behavior are limited. Moreover, from the literature it is not yet clear what type of interventions work best, for whom and in what context.

Acceptability and potential effectiveness of commercial portion control tools amongst people with obesity.

Exposure to large portion sizes is a risk factor for obesity. Specifically designed tableware may modulate how much is eaten and help with portion control. We examined the experience of using a guided crockery set (CS) and a calibrated serving spoon set (SS) by individuals trying to manage their weight. Twenty-nine obese adults who had completed 7-12 weeks of a community weight-loss programme were invited to use both tools for 2 weeks each, in a crossover design, with minimal health professional contact. A paper-based questionnaire was used to collect data on acceptance, perceived changes in portion size, frequency, and type of meal when the tool was used. Scores describing acceptance, ease of use and perceived effectiveness were derived from five-point Likert scales from which binary indicators (high/low) were analysed using logistic regression. Mean acceptance, ease of use and perceived effectiveness were moderate to high (3·7-4·4 points). Tool type did not have an impact on indicators of acceptance, ease of use and perceived effectiveness (P>0·32 for all comparisons); 55 % of participants used the CS on most days v. 21 % for the SS. The CS was used for all meals, whereas the SS was mostly used for evening meals. Self-selected portion sizes increased for vegetables and decreased for chips and potatoes with both tools. Participants rated both tools as equally acceptable, easy to use and with similar perceived effectiveness. Formal trials to evaluate the impact of such tools on weight control are warranted.

Eating less from bigger packs: Preventing the pack size effect with diet primes.

An increase in the package size of food has been shown to lead to an increase in energy intake from this food, the so-called pack size effect. Previous research has shown that providing diet-concerned individuals with a reminder, or prime, of their dieting goal can help them control their consumption. Here, we investigated if providing such a prime is also effective for reducing the magnitude of the pack size effect. We conducted two experiments in which the cover of a dieting magazine (Experiment 1) and diet-related commercials (Experiment 2) served as diet goal primes. Both experiments had a 2 (pack size: small vs. large) × 2 (prime: diet vs. control) × 2 (dietary restraint: high vs. low) between participants design. We measured expected consumption of four snack foods in Experiment 1 (N = 477), and actual consumption of M&M's in Experiment 2 (N = 224). Results showed that the diet prime reduced the pack size effect for both restrained and unrestrained eaters in Experiment 1 and for restrained eaters only in Experiment 2. Although effect sizes were small, these findings suggest that a diet prime motivates restrained eaters to limit their consumption, and as a result the pack size has less influence on the amount consumed. We discuss limitations of this research as well as potential avenues for further research and theoretical and practical implications.

Secular trends in reported portion size of food and beverages consumed by Irish adults.

The present analysis aimed to investigate the changes in the reported portion sizes (PS) of foods and beverages commonly consumed by Irish adults (18-64 years) from the North South Ireland Food Consumption Survey (NSIFCS) (1997-2001) and the National Adult Nutrition Survey (NANS) (2008-10). Food PS, which are defined as the weight of food (g) consumed per eating occasion, were calculated for comparable foods and beverages in two nationally representative cross-sectional Irish food consumption surveys and were published in NSIFCS and NANS. Repeated measure mixed model analysis compared reported food PS at the total population level as well as subdivided by sex, age, BMI and social class. A total of thirteen commonly consumed foods were examined. The analysis demonstrated that PS significantly increased for five foods ('white sliced bread', 'brown/wholemeal breads', 'all meat, cooked', 'poultry, roasted' and 'milk'), significantly decreased for three ('potatoes', 'chips/wedges' and 'ham, sliced') and did not significantly change for five foods ('processed potato products', 'bacon/ham', 'cheese', 'yogurt' and 'butter/spreads') between the NSIFCS and the NANS. The present study demonstrates that there was considerable variation in the trends in reported food PS over this period.

One man's tall is another man's small: how the framing of portion size influences food choice.

Labels such as 'Large' or 'Super-size' are often used to describe portion sizes. How do these normative labels influence consumer choice and how much they ultimately either consume or waste? Although one might believe that firms use normative labels to impact choice behavior through loss aversion, a field experiment shows consumer's willingness to pay is inconsistent with a loss aversion explanation. Although portions were clearly visible, individuals appeared to use the labels as objective information about their size. Importantly, a second study showed these labels also led people to eat less when food was given a larger sounding name than a smaller name (double vs. regular; regular vs. half-size). If labels are used as size information, policies governing normative names could help reduce food consumption or reduce waste.