Effectiveness of Differing Levels of Support for Family Mealtimes on Obesity Prevention Among Head Start Preschoolers
Phase: NA
Conditions: Obesity
Sponsor: Michigan State University

 
Effectiveness of Differing Levels of Support for Family Mealtimes on Obesity 
Prevention Among Head Start Preschools 
 
Trial #: NCT02487251 
 
Protocols and Analytic Plans 
Originally Submitted: 7/14/21 
Updated: 9/27/21 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Phase 1 Study Protocol 
In a factorial design with six intervention components reflecting supports for family 
mealtimes (e.g., meal delivery, cookware/dinnerware provision, nutrition education, etc.), 
individual participants were randomized to one of 64 experimental conditions. The 64 
experimental conditions result from the crossing of six interventions, each of which had two 
conditions (present vs. not) and reflect all possible pairings of the intervention components 
including a condition with no intervention components. Feasibility was assessed via 
attendance/participation in intervention components. The intervention period was 8 weeks.  
Families were recruited from two Head Start agencies serving a mix of rural and urban 
areas in mid-Michigan. Participants were recruited on-site at their children’s Head Start 
programs during parent events or through informational packets that were sent home in 
children’s backpacks.  Parents expressing an interest in study participation were screened for 
eligibility. Written consent was obtained from all participants during a home visit. Families were 
assigned to study interventions through an automated random number generator.   
Data collection teams were distinct from the intervention staff and were managed 
separately. Evaluators of study outcomes were blinded to the intervention components to which 
participants were assigned. After obtaining written informed consent and prior to starting the 
intervention, a data collector made a home visit to measure maternal and child weight and height 
and complete a series of questionnaires with the mother.  Following the implementation of the 
intervention, a parallel post-intervention data collection visit was conducted.  
 
Phase 2 Study Protocol 

Families were enrolled, consented and randomly assigned to the intervention or to usual 
care control group.  Outcome measures were collected both pre- and post-intervention while data 
on dietary quality were also collected mid-intervention. Most data were collected in the home; 
however, with the onset of the global COVID-19 pandemic, data collection was moved to an 
online platform through which participants completed self-reported questionnaires.  Because in-
person data collection efforts were not possible, measurements of child height/weight and data 
on mealtime interactions were not collected for participants with data collection points falling 
after March 2020.  Families received written and verbal information about the study and 
provided written informed consent.  Data collectors and interventionists did not interact, and data 
collectors were blinded.  Participants in the intervention condition received two meals per week 
for 12 weeks and they received a comprehensive set of cookware/dinnerware at the outset of the 
intervention delivery.  
 
Phase 1 Analytic Plan 
The results of the six intervention components were identified by means of a factorial 
experiment involving the following factors: 1) Meal Delivery (provided vs. not); 2) Ingredient 
Delivery (provided vs. not); 3) Community Kitchen (provided vs. not); 4) Didactic Nutrition 
Education Classes (provided vs. not); 5) Cooking Lessons (provided vs. not); and 6) 
Cookware/Materials Provision (provided vs. not). Pre- to post-intervention change scores were 
calculated for each intervention condition. Using Cohen’s d to assess effect sizes of pre-post 
changes for each primary and secondary outcome, results were categorized using the following a 
priori thresholds for interpretation and compared to the control condition: small (d≤.30), medium 
(d>.31 and ≤.50), and large (d≥.80). This emphasis was consistent with our objective of 
identifying a feasible, final set of bundled components. Then, paired t-tests were conducted to 

examine pre- to post-intervention changes within the intervention combinations that included 
Meal Delivery and Cookware/Materials Provision (N = 65), identified as the two most feasible, 
and promising intervention components.  Because sample sizes within each of the intervention 
combinations were small and because participation in all interventions except Meal Delivery, 
Ingredient Delivery and Cookware/Materials provisions was so negligible (described in the 
results), we elected to use combined samples in the paired t-tests analyses. Thus, the 65 
participants received Meal Delivery and Cookware/Materials Provision but may have also 
received other interventions except for Ingredient Delivery.  The rationale for this was that the 
extremely low participation in Community Kitchen, Nutrition Education, and Cooking 
Demonstrations would result in no intervention effects related specifically to these intervention 
components. As a caution, we also examined pre-post analyses with the small group of 
participants who only received Meal Delivery and Cookware/Materials Provision.   
 
Phase 2 Analytic Plan 
Sample size was set at 125 per arm which, with 20% attrition, would enable detection of 
small to medium effect sizes of d = 0.40SD for continuous outcomes and 38% relative risk 
reduction for binary outcomes with a power of 80% and α = .05.  Baseline comparability of the 
intervention and control arms was assessed using two sample t-tests and chi-square. Baseline 
comparability of the full MOW cohort (intervention plus control) and full COM cohort 
(intervention plus control), baseline comparability of the MOW intervention and MOW control, 
as well as the COM intervention and COM control were assessed in the same manner. Mixed 
models were used to account for having repeated measures (pre and post).  All analyses were 
done in SAS 9.4 and were adjusted for child’s sex.  Models of BMIz and dietary measures were 
also adjusted for season of data collection (summer vs. school year) as seasonal differences were 

seen in the baseline data for these measures and seasonal differences in preschoolers’ BMIz have 
been reported in the literature (e.g., Lumeng et al., 2015). Additionally, models in the MOW 
sample adjusted for family structure and models in the COM sample adjusted for income-to-
needs ratio, given baseline differences between the control and intervention groups within these 
cohorts.  Analyses were based on the intention to treat principle such that all randomized 
participants were included in the analysis based on their randomized intervention group.  
Significance was assessed using a two-sided test at α= 0.05.