Effectiveness of Behavioral Economics-Informed Strategies and Enhanced Food Preparation Skills to Increase Vegetable Intake and Variety of Vegetables Eaten among Low-Income Children

Abstract

Obesity prevalence among children continues to be a serious problem, especially for those in low-income households. Inadequate vegetable intake leading to low dietary quality may be a contributing factor to the obesity problem among children. The field of behavioral economics has gained momentum in nutrition interventions for improving vegetable intake, mainly in school and other cafeteria settings, using low-to-no cost modifications to the food environment. Similar strategies have yet to be tested in the home in a large-scale trial. The overall objective of the following dissertation was to determine if an intervention comprised of 6 behavioral economics-informed strategies within a 6-session vegetable-focused cooking skills program, grounded in Social Cognitive Theory, was more effective for improving vegetable intake, vegetable liking, variety of vegetable eaten, BMI-z score, and home availability of vegetables for a diverse sample of low-income children (ages 9-12) than a control condition of the vegetable-focused cooking skills program alone. The 6 strategies tested were: 1) child helping to prepare the vegetables, 2) using a plate that shows the appropriate proportion of food groups within a meal, 3) making the vegetables the most available and visible part of the meal, 4) serving at least 2 vegetables with the meal, 5) serving the vegetables before the meal, and 6) using a bigger spoon to serve the vegetables. The three separate reports included in this dissertation utilized data collected in a longitudinal controlled intervention trial conducted in the Minneapolis-St. Paul metropolitan area from September 2014-June 2017. Outcome measures were collected at 4 time points: baseline, immediate post-course, 6-months post-course, and 12-months post-course. Mixed model regression analyses and t-tests were used to compare outcomes between intervention and control groups. A total of 103 parent/child pairs were enrolled with 91 who completed the weekly cooking skills program. The child outcomes of vegetable intake, vegetable liking, variety of vegetables eaten, and BMI-z score, as well as home availability of vegetables were not improved for the intervention children more than the control children. The immediate impact of the vegetable-focused cooking skills program on parent and child psychosocial measures (e.g. cooking self-efficacy and interest in cooking) was assessed. Baseline and immediate post-course survey data from the intervention and control groups were combined since both groups participated in the cooking skills program. The combined data were used to assess changes in outcome measures from pre- to post-course. Validated parent self-report questionnaires were used to assess changes in the following psychosocial outcomes: cooking confidence, healthy food preparation, cooking barriers, and food resource management. Parents and children were asked if they had ever tried each of 37 different vegetables and if yes, to rate their liking. Changes between pre- and post-course responses were tested using paired t-tests or Wilcoxon signed-rank tests. Improvements were observed for parental cooking confidence, healthy food preparation skills, number of vegetables present in the home, parental vegetable liking, parental variety of vegetables eaten, and confidence in cooking individual vegetables and using several vegetable cooking methods. Improvements were also observed for child cooking self-efficacy and variety of vegetables eaten. Vegetable liking and acceptability for a wide variety of vegetables was measured among a racially and ethnically diverse sample of 9-12 year old children. Child liking data were combined from the present study and another in-home intervention study with a similar study population. Mean liking ratings for each vegetable were calculated. The number of children that found each vegetable acceptable and unacceptable was also tabulated. The most liked vegetables were corn, potatoes, lettuce, and carrots. Artichoke, onion, and beets were the 3 vegetables with the lowest mean liking. Overall, children found a wide variety of vegetables acceptable.