Donna Matheson

Visual illusions and plate design: the effects of plate rim widths and rim coloring on perceived food portion size

Objective:The Delboeuf Illusion affects perceptions of the relative sizes of concentric shapes. This study was designed to extend research on the application of the Delboeuf illusion to food on a plate by testing whether a plate’s rim width and coloring influence perceptual bias to affect perceived food portion size.Design and methods:Within-subjects experimental design. Experiment 1 tested the effect of rim width on perceived food portion size. Experiment 2 tested the effect of rim coloring on perceived food portion size. In both experiments, participants observed a series of photographic images of paired, side-by-side plates varying in designs and amounts of food. From each pair, participants were asked to select the plate that contained more food. Multilevel logistic regression examined the effects of rim width and coloring on perceived food portion size.Results:Experiment 1: participants overestimated the diameter of food portions by 5% and the visual area of food portions by 10% on plates with wider rims compared with plates with very thin rims (P<0.0001). The effect of rim width was greater with larger food portion sizes. Experiment 2: participants overestimated the diameter of food portions by 1.5% and the visual area of food portions by 3% on plates with rim coloring compared with plates with no coloring (P=0.01). The effect of rim coloring was greater with smaller food portion sizes.Conclusion:The Delboeuf illusion applies to food on a plate. Participants overestimated food portion size on plates with wider and colored rims. These findings may help design plates to influence perceptions of food portion sizes.

Family, community and clinic collaboration to treat overweight and obese children: Stanford GOALS—A randomized controlled trial of a three-year, multi-component, multi-level, multi-setting intervention

OBJECTIVE To test the effects of a three-year, community-based, multi-component, multi-level, multi-setting (MMM) approach for treating overweight and obese children. DESIGN Two-arm, parallel group, randomized controlled trial with measures at baseline, 12, 24, and 36 months after randomization. PARTICIPANTS Seven through eleven year old, overweight and obese children (BMI ≥ 85th percentile) and their parents/caregivers recruited from community locations in low-income, primarily Latino neighborhoods in Northern California. INTERVENTIONS Families are randomized to the MMM intervention versus a community health education active-placebo comparison intervention. Interventions last for three years for each participant. The MMM intervention includes a community-based after school team sports program designed specifically for overweight and obese children, a home-based family intervention to reduce screen time, alter the home food/eating environment, and promote self-regulatory skills for eating and activity behavior change, and a primary care behavioral counseling intervention linked to the community and home interventions. The active-placebo comparison intervention includes semi-annual health education home visits, monthly health education newsletters for children and for parents/guardians, and a series of community-based health education events for families. MAIN OUTCOME MEASURE Body mass index trajectory over the three-year study. Secondary outcome measures include waist circumference, triceps skinfold thickness, accelerometer-measured physical activity, 24-hour dietary recalls, screen time and other sedentary behaviors, blood pressure, fasting lipids, glucose, insulin, hemoglobin A1c, C-reactive protein, alanine aminotransferase, and psychosocial measures. CONCLUSIONS The Stanford GOALS trial is testing the efficacy of a novel community-based multi-component, multi-level, multi-setting treatment for childhood overweight and obesity in low-income, Latino families.

Deconstructing interventions: approaches to studying behavior change techniques across obesity interventions

Deconstructing interventions into the specific techniques that are used to change behavior represents a new frontier in behavioral intervention research. This paper considers opportunities and challenges in employing the Behavior Change Techniques Taxonomy (BCTTv1) developed by Michie and colleagues, to code the behavior change techniques (BCTs) across multiple interventions addressing obesity and capture dose received at the technique level. Numerous advantages were recognized for using a shared framework for intervention description. Coding interventions at levels of the social ecological framework beyond the individual level, separate coding for behavior change initiation vs. maintenance, fidelity of BCT delivery, accounting for BCTs mode of delivery, and tailoring BCTs, present both challenges and opportunities. Deconstructing interventions and identifying the dose required to positively impact health-related outcomes could enable important gains in intervention science.

Effects of Varying Epoch Lengths, Wear Time Algorithms, and Activity Cut-Points on Estimates of Child Sedentary Behavior and Physical Activity from Accelerometer Data

Objective To examine the effects of accelerometer epoch lengths, wear time (WT) algorithms, and activity cut-points on estimates of WT, sedentary behavior (SB), and physical activity (PA). Methods 268 7–11 year-olds with BMI ≥ 85th percentile for age and sex wore accelerometers on their right hips for 4–7 days. Data were processed and analyzed at epoch lengths of 1-, 5-, 10-, 15-, 30-, and 60-seconds. For each epoch length, WT minutes/day was determined using three common WT algorithms, and minutes/day and percent time spent in SB, light (LPA), moderate (MPA), and vigorous (VPA) PA were determined using five common activity cut-points. ANOVA tested differences in WT, SB, LPA, MPA, VPA, and MVPA when using the different epoch lengths, WT algorithms, and activity cut-points. Results WT minutes/day varied significantly by epoch length when using the NHANES WT algorithm (p < .0001), but did not vary significantly by epoch length when using the ≥ 20 minute consecutive zero or Choi WT algorithms. Minutes/day and percent time spent in SB, LPA, MPA, VPA, and MVPA varied significantly by epoch length for all sets of activity cut-points tested with all three WT algorithms (all p < .0001). Across all epoch lengths, minutes/day and percent time spent in SB, LPA, MPA, VPA, and MVPA also varied significantly across all sets of activity cut-points with all three WT algorithms (all p < .0001). Conclusions The common practice of converting WT algorithms and activity cut-point definitions to match different epoch lengths may introduce significant errors. Estimates of SB and PA from studies that process and analyze data using different epoch lengths, WT algorithms, and/or activity cut-points are not comparable, potentially leading to very different results, interpretations, and conclusions, misleading research and public policy.

Content Analysis of the Use of Fantasy, Challenge, and Curiosity in School-Based Nutrition Education Programs

The objective of this research was to document the extent to which elements of fantasy, curiosity, and challenge are used in existing nutrition education materials. A content analysis of 30 nutrition education curricula designed for elementary and middle-school grades was conducted. Print curricula, computer software, videotapes, and puppet shows were included in the sample. The use of challenge, curiosity, and fantasy, as defined in the Theory of Intrinsically Motivating Instruction (TIMI), was assessed in each curriculum. Approximately half of the curricula included elements of challenge, curiosity, or fantasy. All of the nonprint curricula and 30% of the print curricula incorporated these characteristics. Curiosity was most frequently used in these curricula, followed by fantasy and then challenge. The TIMI provided a useful theory to examine the instructional approaches frequently used in school-based nutrition education programs. Nutritionists may apply concepts from the TIMI to the design of future curricula so that these programs are interesting and entertaining for their target audience.

Description of a Process Evaluation Model for Nutrition Education Computer-Assisted Instruction Programs

Abstract Computers have been promoted as a tool to facilitate learning. Subsequently, health education software programs have been developed, but few of these programs have been evaluated. Little is known about how students use or learn from computer-assisted instruction (CAI). Qualitative research methods are needed to reveal the critical issues related to CAI in nutrition education and establish the direction for future research. The purpose of this paper is to describe a process evaluation model that was used to test a nutrition education CAI program for middle school students. The specific outcome that was measured was learning. Learning was assessed by changes in students’ cognitive structures of basic nutrition concepts included in the program. Concept maps were used to represent students’ cognitive structure and were constructed from data collected by semistructured interviews with children before and after they completed the program. Context was defined by students’ interaction with the computer and with other students. These data were collected by observation and analyzed by grounded theory methods.The value of the model is in the integration of measurements of change and context. Together, change and context provide a dynamic, continuous, and inductive evaluation of the learning process and the effectiveness of a nutrition education program.

Reporting of treatment fidelity in behavioural paediatric obesity intervention trials: a systematic review

Behavioural interventions for paediatric obesity are promising, but detailed information on treatment fidelity (i.e. design, training, delivery, receipt and enactment) is needed to optimize the implementation of more effective interventions. Little is known about current practices for reporting treatment fidelity in paediatric obesity studies. This systematic review, in accordance with Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines, describes the methods used to report treatment fidelity in randomized controlled trials. Treatment fidelity was double‐coded using the National Institutes of Health Fidelity Framework checklist. Three hundred articles (N = 193 studies) were included. Mean inter‐coder reliability across items was 0.83 (SD = 0.09). Reporting of treatment design elements within the field was high (e.g. 77% of studies reported designed length of treatment session), but reporting of other domains was low (e.g. only 7% of studies reported length of treatment sessions delivered). Few reported gold standard methods to evaluate treatment fidelity (e.g. coding treatment content delivered). General study quality was associated with reporting of treatment fidelity (p < 0.01) as was the number of articles published for a given study (p < 0.01). The frequency of reporting treatment fidelity components has not improved over time (p = 0.26). Specific recommendations are made to support paediatric obesity researchers in leading health behaviour disciplines towards more rigorous measurement and reporting of treatment fidelity.

Environmental Strategies for Portion Control in Children

Evidence from laboratory and field studies indicates that large portions lead to greater food and energy intake relative to small portions. However, most children and adults demonstrate limited abilities to estimate and control the amounts of food they serve and consume. Five potential environmental strategies appear promising for improving portion control in children: (1) using tall, thin, and small volume glasses and mugs, (2) using smaller diameter and volume plates, bowls and serving utensils, (3) using plates with rims, (4) reducing total television and other screen watching and (5) reducing or eliminating eating while watching television and/or other screens. Further experimental research in real world settings is needed to test these interventions as strategies for portion control and their roles in prevention and treatment of obesity.

Beyond the dinner table: Who's having breakfast, lunch and dinner family meals and which meals are associated with better diet quality and BMI in pre-school children?

OBJECTIVE Having frequent family dinners is associated with better diet quality in children; however, it is unknown whether the frequency of certain family meal types (i.e. dinner) is more strongly associated with better child weight and diet quality compared with other meal types (i.e. breakfast, lunch). Thus, the current study examined the frequency of eating breakfast, lunch or dinner family meals and associations with pre-school childrens overall diet quality (HEI-2010) and BMI percentile. DESIGN Cross-sectional baseline data (2012-2014) from two randomized controlled childhood obesity prevention trials, NET-Works and GROW, were analysed together. SETTING Studies were carried out in community and in-home settings in urban areas of Minnesota and Tennessee, USA. SUBJECTS Parent-child (ages 2-5 years) pairs from Minnesota (n 222 non-Hispanics; n 312 Hispanics) and Tennessee (n 545 Hispanics; n 55 non-Hispanics) participated in the study. RESULTS Over 80 % of families ate breakfast or lunch family meals at least once per week. Over 65 % of families ate dinner family meals ≥5 times/week. Frequency of breakfast family meals and total weekly family meals were significantly associated with healthier diet quality for non-Hispanic pre-school children (P<0·05), but not for Hispanic children. Family meal frequency by meal type was not associated with BMI percentile for non-Hispanic or Hispanic pre-school children. CONCLUSIONS Breakfast family meal frequency and total weekly family meal frequency were associated with healthier diet quality in non-Hispanic pre-school children but not in Hispanic children. Longitudinal research is needed to clarify the association between family meal type and child diet quality and BMI percentile.