Fruits and Vegetables Displace, But Do Not Decrease, Total Energy in School Lunches

Abstract

Background: The high overweight and obesity prevalence among US children is a well-established public health concern. Diet is known to play a causal role in obesity. Increasing fruit and vegetable (FV) consumption to recommended levels is proposed to help reduce obesity, because their bulk and low energy density are believed to reduce energy-dense food consumption (volume displacement hypothesis). This study tests this hypothesis at the lunch meal among upper-elementary students participating in a Farm to School (F2S) program.Methods: Digital photographs of students' school lunch trays were visually analyzed to identify the food items and amounts that were present and consumed before and after the meal. Using the USDA Nutrient Database, total and FV-only energy were calculated for each tray. Analysis of total-and non-FV energy intake was performed according to (1) levels of FV energy intake, (2) FV energy density, and (3) previous years of Farm to School programming.Results: Higher intake of FV energy displaced non-FV energy, but total energy did not decrease across FV energy intake groups. High-FV-energy-density trays showed lower non-FV energy intake than low-FV-energy-density trays (470 -179 vs. 534 -219 kcal; p < 0.0001). Trays from schools with more previous years of F2S programming decreased total and non-FV energy intake from school lunches ( p for trend < 0.0001, both).Conclusions: Increased FV consumption reduces non-FV energy intake, but does not reduce total energy intake. Therefore, this study does not support the volume displacement hypothesis and suggests calorie displacement instead.

Factors Related to Fruit and Vegetable Consumption at Lunch Among Elementary Students: A Scoping Review

“…The average number of schools sampled was 7.7 (standard deviation, 11.1; range, 1–60). Of studies conducted in more than one school (35 studies), 15 studies ( 18 , 20 – 22 , 25 , 38 , 41 , 45 , 46 , 49 , 50 , 53 , 57 , 60 , 64 ) reported using a statistical method that accounted for clustering. Most studies (30 studies) sampled from schools in which more than half of students were eligible for free or reduced-price lunch; 7 studies did not report this characteristic ( 26 , 28 , 32 , 35 , 52 , 54 , 58 ).…”

“…The methods used to assess fruit and vegetable consumption varied: 19 studies used weighed plate waste ( 16 , 24 , 30 , 32 , 34 – 37 , 40 – 42 , 44 , 45 , 50 , 52 , 56 , 58 , 60 , 64 ), 15 studies used direct observation ( 17 , 25 – 27 , 29 , 31 , 33 , 39 , 46 , 47 , 54 , 56 , 57 , 59 , 63 ), 12 studies used digital photography ( 18 – 20 , 22 , 23 , 28 , 48 , 49 , 52 , 55 , 61 , 62 ), and 4 studies used a self-report instrument that included 24-hour recalls, food records, or questionnaires ( 21 , 38 , 43 , 51 ). On average, studies collected data on fruit and vegetable consumption across a total of 23 school days; the mode for duration of data collection was 5 days.…”

Food Waste in the National School Lunch Program 1978-2015: A Systematic Review

“…The purposes of each study varied, with food waste measures aimed at primarily understanding the amount of food waste 22 , 31 and food consumption, 25 , 27 , 28 modification of food environment or lunchtime procedures, 26 , 29 instrument validity, 23 compliance with nutrition recommendations, 24 and nutrition education. 30 , 32 Studies were conducted in the West, 25 , 26 Midwest, 27 , 28 , 30 , 31 Northeast, 29 and South, 22 , 24 , 32 although one did not report geographic location. 23 Alaimo and colleagues 30 and Monlezun and colleagues 32 reported free and reduced rates near 100%, whereas several other studies did not report free and reduced rates.…”

“… 25 , 27 , 29 Several studies expressed food waste in terms of calories rather than as a percentage of food wasted. 26 , 28 , 32 …”

Understanding the Relationship Between Food Variety, Food Intake, and Energy Balance

“…For example, greater variety of foods higher in energy density (high-energy-dense [HED] foods) may increase intake of these foods, contributing to greater overall energy intake. Alternatively, greater variety of foods lower in energy density (low-energy-dense [LED] foods) may increase intake of these foods, and due to their energy density may not significantly increase energy intake, or may actually assist with reducing energy intake if increased consumption of LED foods reduces intake of HED foods due to the occurrence of substitution or displacement [44].…”