The Influence of Portion Size on Eating and Drinking

There is growing interest in the role of large portions in overeating. Experimental studies consistently demonstrate that serving large amounts of food leads individuals to consume more food and energy than they require. This portion size effect has been observed across different types of foods and beverages and can be sustained over several months. Furthermore, there is evidence that prolonged provision of large portions can lead to weight gain. The robust nature of this effect has led to efforts to identify strategies to manage food and beverage portions. Certain characteristics of the consumer (e.g., satiety responsiveness, slowness of eating) and the available food (e.g., relative palatability, value) have been found to influence the effect of portion size, and these are potential targets for interventions to attenuate the response. To date, the most reliable and effective method to moderate energy intake from large portions is reducing the energy density of the diet. Future studies need to build on current knowledge to understand individual and contextual variability in the response to portion size. A more comprehensive understanding of the portion size effect can lead to the development of a systems approach in which the food, individual, and environment are targeted simultaneously to counter the effects of large portions.