Nutrition Environment Measures Study in Restaurants (NEMS-R)

Background

Americans are increasingly eating out, but nutrition environments in restaurants are poorly understood. An observational measure was developed to assess factors believed to contribute to food choices in restaurants, including availability of more healthy foods, facilitators and barriers to healthful eating, pricing, and signage/promotion of healthy and unhealthy foods.

Methods

Inter-rater and test–retest reliability were assessed in 217 sit-down and fast-food restaurants in four neighborhoods in 2004 and 2005.

Results

Inter-rater reliability was generally high, with most kappa values greater than 0.80 (range 0.27–0.97) and all percent-agreement values greater than 75% (77.6–99.5). Test–retest reliability was high, with most kappa values greater than 0.80 (0.46–1.0) and all percent-agreement values greater than 80% (80.4–100). There were several differences (p<0.05) between nutrition environment variables in sit-down versus fast-food restaurants, although neither restaurant type was consistently more healthful. Fast-food restaurants had greater healthy entrée and main-dish salad availability, but sit-down restaurants had a higher proportion of healthy main-dish salads and more healthy food and beverage items. Fast-food restaurants more often encouraged large portions, unhealthful eating, and overeating, and offered relative cost savings for combination meals, but were also more likely to provide nutrition information and highlight healthy options.

Conclusions

Testing hypotheses about food environment influences on obesity and eating patterns requires psychometrically sound measurement of nutrition environments. This Nutrition Environment Measures Study restaurant assessment (NEMS-R) has evidence of reliability, and can discriminate restaurant types. The NEMS-R can be used in research and practice to characterize restaurant environments.

Introduction

The proportion of meals eaten outside the home has increased in the United States1, 2 among children and adults.3, 4, 5 Greater reliance on restaurants has potential negative nutritional and health consequences because individuals eating at restaurants more frequently have higher average caloric and fat intake, and lower fruit, vegetable, and fiber consumption.1, 6, 7, 8, 9, 10 Frequency of eating in restaurants is positively related to weight and increases in weight,8, 11, 12 perhaps due to many unhealthy choices available in restaurants and resultant higher energy consumption.1, 13, 14

Fast-food restaurants have been identified as a potential contributor to higher obesity prevalence.¹⁵ Higher concentrations of fast-food restaurants in poorer neighborhoods16, 17, 18, 19 and less healthful options within fast-food restaurants²⁰ may partially explain higher obesity prevalence among economically disadvantaged populations. The density of fast-food restaurants accounted for 6% of the variance in obesity prevalence across United States.²¹ However, the evidence to date about the relationship between individuals’ weight status to their surrounding neighborhoods’ restaurant density is weak. Sturm and Datar²² found that young children’s increases in body mass index were related more to metropolitan-level estimates of fruit and vegetable prices than overall restaurant or restaurant type (e.g., fast food versus sit down) density. Restaurant density has been found to be unrelated to adults’ obesity prevalence,²³ and proximity to the nearest fast-food restaurant was unrelated to overweight prevalence in lower income children.²⁴

There is a considerable limitation of using restaurant proximity as a proxy for individuals’ food environment. This assumes that all restaurants, or at best all restaurants of the same type, have the same dietary quality, food promotion environment, and pricing. It is likely the consumer nutrition environment, that is, the environment consumers’ experience within restaurants, differs appreciably among restaurants, and could be influencing patrons’ eating patterns.²⁵ Consumer nutrition environments within restaurants may differ in the availability of healthier menu options, nutrition information, and signage/promotion regarding specific foods or eating in general. However, research on the environment within restaurants is limited. Two studies26, 27 found low rates of low-fat menu items in restaurants. Extending findings of racial and socioeconomic disparities in the distribution of restaurants, a recent study²⁸ found less health promotion and fewer healthy food choices in restaurants in predominantly African-American ZIP codes in Los Angeles.

There have been advancements in the measurement of food environments within restaurants, including good interobserver reliability for availability of fruits and vegetables.²⁹ Cassady and colleagues³⁰ developed a restaurant menu checklist for use by community members that assesses food preparation, number of healthful choices, and fruit/vegetable availability. However, this checklist did not assess the whole restaurant environment, and was tested in only 14 family-style restaurants. Further, the checklist did not evaluate price comparisons between unhealthy and healthy alternatives despite the central role of price in food selection.31, 32

To understand the relationship of food environments to eating and weight patterns, measures of neighborhood food access need to integrate restaurant accessibility with attributes of the food environment within restaurants. Measures are needed that evaluate the wide range of environmental stimuli faced by consumers within restaurants that may affect food choices. The present paper describes the development and evaluation of an observational measure of the “consumer nutrition environment” within restaurants. The instrument’s test–retest reliability, inter-rater reliability, and the ability to discriminate based on restaurant type were assessed.