Portioning meat and vegetables in four different out of home settings: A win-win for guests, chefs and the planet.

Individuals increasingly consume their meals away from home. This article describes a series of studies that examined the effects of meals with reduced amounts of meat and increased amounts of vegetables on food consumption, waste and guest satisfaction in four real-life restaurant settings in the Netherlands: an a-la-carte restaurant, six company canteens, a self-service restaurant, and a buffet restaurant, including nearly 1500 participants in total. The four studies in these four different out of home settings consistently showed that adapting portion sizes of meat and vegetables was effective to reduce meat consumption and increase vegetable consumption, while maintaining high guest satisfaction. Guest satisfaction even increased when vegetables were presented and prepared in a more attractive and tasty way. Thus, adapting portion sizes of meat and vegetables provides a viable strategy to stimulate healthy and environmentally sustainable consumption patterns in out of home settings.

Menu-engineering in restaurants - adapting portion sizes on plates to enhance vegetable consumption: a real-life experiment.

BACKGROUND: The aim of this research was to investigate whether increased portion sizes of vegetables and decreased portion sizes of meat on main dishes increased the amount of vegetables consumed in a real-life restaurant setting without affecting customer satisfaction. The participants were unaware of the experiment. METHODS: A cross-over design was used in which three restaurants were randomly assigned to a sequence of an intervention and control condition. In the intervention period, the vegetable portion sizes on the plates of main dishes were doubled (150 g of vegetables instead of 75 g) and the portion sizes of meat on the plates were reduced by an average of 12.5%. In the control period, the portion sizes of the main dishes were maintained as usual. In total, 1006 observations and questionnaires were included. RESULTS: Vegetable consumption from plates was significantly higher during the intervention period (M = 115.5 g) than during the control period (M = 61.7 g). Similarly, total vegetable consumption (including side dishes) was significantly higher during the intervention period (M = 178.0 g) than during the control period (M = 137.0 g). Conversely, meat consumption was significantly lower during the intervention period (M = 183.1 g) than during the control period (M = 211.1 g). Satisfaction with the restaurant visit did not differ between the intervention period (M = 1.27) and control period (M = 1.35). Satisfaction with the main dish was significantly lower during the intervention period (M = 1.25) than during the control period (M = 1.38), although in both cases, the scores indicated that participants remained (very) satisfied with their main dish. CONCLUSIONS: This study showed that increasing vegetable portions in combination with decreasing meat portions (unknowingly to the consumer) increased the amount of vegetables consumed and decreased the amount of meat consumed. Furthermore, despite the changes in portion sizes, participants remained satisfied with their restaurant visit and main dish. The findings of this study suggest that modifying portion size in restaurants is an effective tool for stimulating vegetable consumption and consequently healthy and sustainable diets.