Effects of Longer Seated Lunch Time on Food Consumption and Waste in Elementary and Middle School-age Children: A Randomized Clinical Trial.

Importance: Health experts recommend at least 20 minutes of seated lunch time for children, but no federal policy for lunch period duration exists in the United States. Additional strategies in the National School Lunch Program for mitigating food waste are needed to maintain the viability of the Healthy, Hunger-Free Kids Act.

Objective: To assess the effect of a longer seated lunch time on food consumption and waste among elementary and middle school-age children.

Design, Setting, And Participants: This randomized within-participant crossover trial was conducted from June 3 to June 28, 2019, for a total of 20 study days. All attendees of a summer camp held at the University of Illinois at Urbana-Champaign, were invited to participate in the study. Participants were elementary and middle school-age children and were provided every study day with lunch prepared according to the National School Lunch Program nutrition standards.

Intervention: Five menus were served throughout the study. A 20-minute or 10-minute seated lunch condition was randomly assigned to each day within the 5 menus.

Main Outcomes And Measures: The primary outcomes were food consumption, waste, and dietary intake, which were analyzed separately for each meal component (fruit, vegetable, entree [protein plus grain], beverage [both milk and water], and milk alone). Dietary intake was assessed for calories, fat, carbohydrates, fiber, protein, vitamin D, calcium, iron, and potassium. Participant behaviors were observed during the meal, including seated time as well as level of talking and phone use.

Results: A total of 38 children with 241 lunch trays were observed. The 38 children had a mean (SD) age of 11.86 (1.23) years and 23 were female participants (61%); 30 had a non-Hispanic/non-Latino ethnicity (79%) and 23 were White individuals (61%). During 10 minutes of seated lunch time, participants consumed significantly less fruit (-11.3 percentage points; 95% CI, -18.1 to -4.5) and vegetables (-14.1 percentage points; 95% CI, -22.7 to -5.7) compared with 20 minutes of seated lunch time. Entree and beverage consumption and waste did not differ between the 10-minute and 20-minute seated lunch conditions. Participants also consumed significantly more and wasted significantly less calories (-22.03 kcal; 95% CI, -39.47 to -4.61 kcal), carbohydrates (-3.81 g; 95% CI, -6.20 to -1.42 g), dietary fiber (-0.51 g; 95% CI, -0.81 to -0.19 g), protein (-1.11 g; 95% CI, -2.17 to -0.04 g), iron (-0.20 mg; 95% CI, -0.38 to -0.02 mg), and potassium (-53.49 mg; 95% CI, -84.67 to -22.32 mg) during the 20-minute seated lunch condition.

Conclusions And Relevance: This study found that fruit and vegetable consumption increased in school-age children during a 20-minute seated lunch condition. This finding supports policies that require children to receive at least 20 minutes of seated lunch time; such policies could have favorable implications for children's dietary intake and food waste.

Trial Registration: ClinicalTrials.gov Identifier: NCT04191291.