children aged 2 to 5 years who participated in the Continuing Survey of Food Intakes by Individuals (CSFII) 1994-1996, 1998 found that eating behaviors and body weight were positively related to energy intake (McConahy et al., 2004).

Research also suggests that individuals tend to overconsume highenergy-dense foods beyond physiological satiety (Kral et al., 2004), especially when they are unaware that the portion sizes served to them have been substantially increased (Rolls et al., 2004a). Satiety signals are not triggered as effectively with high-energy-dense foods (Drewnowski, 1998), and large portions of them consumed on a regular basis are particularly problematic for achieving energy balance and weight management in older children and adults.

A variety of physiological processes are involved in the regulation of dietary intake, satiety, energy metabolism, and weight. These include the neural pathways that regulate hunger and influence food intake, gastrointestinal mechanisms involved in providing signals to the brain about ingested food, and adipocyte-derived factors that provide information about energy stores, as well as the genetic and environmental factors that affect these physiological processes (see Chapters 3 and 8). There are a variety of external cues that may also influence dietary intake such as portion size and package size. For example, there is some evidence to support the hypothesis that larger food package sizes encourage greater consumption than smaller food package sizes (Wansink, 1996), and external cues such as packaging and container size may contribute to the volume of food consumed (Wansink and Park, 2000).

Thus, although the committee recognizes the difficulties faced by the food industry in developing new packaging options for consumers, industry should explore, through research and test-marketing, the best approaches for modifying product packages—multipackages with smaller individual servings or standard serving sizes, or resealable packages—so that products palatable to consumers may remain profitable while promoting consumption of smaller portions. Moreover, the food industry should investigate other approaches for promoting consumption of smaller portion sizes and standard serving sizes.

Leisure, Entertainment, and Recreation Industries

Americans now enjoy more leisure time than they did a few decades ago. As discussed in Chapter 1, trend data collected by the Americans’ Use of Time Study through time use diaries indicated that adults’ free time increased by 14 percent between 1965 and 1985 to an average total of nearly 40 hours per week (Robinson and Godbey, 1999). Data from other population-based surveys, including the National Health Interview Survey,



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