Elizabeth Velema

Determinants of dietary behavior among youth: an umbrella review

BackgroundThe literature on determinants of dietary behavior among youth is extensive and unwieldy. We conducted an umbrella review or review-of-reviews to present a comprehensive overview of the current knowledge.MethodsTherefore, we included systematic reviews identified in four databases (i.e. PubMed, PsycINFO, The Cochrane Library and Web of Science) that summarized determinants of observable child and adolescent dietary behaviors. Data extraction included a judgment of the importance of determinants, strength of evidence and evaluation of the methodological quality of the eligible reviews.ResultsIn total, 17 reviews were considered eligible. Whereas social-cognitive determinants were addressed most intensively towards the end of the 20th century, environmental determinants (particularly social and physical environmental) have been studied most extensively during the past decade, thereby representing a paradigm shift.With regard to environmental determinants, mixed findings were reported. Sedentary behavior and intention were found to be significant determinants of a wide range of dietary behaviors in most reviews with limited suggestive evidence due to the cross-sectional study designs. Other potential determinants such as automaticity, self-regulation and subjective norm have been studied in relatively few studies, but results are promising.ConclusionThe multitude of studies conducted on potential determinants of dietary behavior provides quite convincing evidence of the importance of several determinants (i.e. quite some variables were significantly related to dietary behavior). However, because of the often used weak research designs in the studies covered in the available reviews, the evidence for true determinants is suggestive at best.

Behavioural strategies to control the amount of food selected and consumed

Several factors within the food environment may stimulate overconsumption. The present study aimed to (1) identify behavioural strategies to cope with this environment to control the amount of food consumed, (2) examine the feasibility and usefulness of the strategies, and (3) evaluate the association between the strategies and body mass index (BMI). After the literature was screened for evidence of factors that contribute to the consumption of large amounts of food, 32 behavioural strategies were identified to overcome these influences (study 1). Subjectively reported feasibility and usefulness of the 32 behavioural strategies in weight management were explored using a pretest post-test study (study 2: n = 52). Additionally, two cross-sectional questionnaire studies (study 3a: n = 120 and study 3b: n = 278) were conducted to evaluate the association between the 32 behavioural strategies and BMI. The strategies were subjectively reported as feasible and useful in weight management. Frequent use of strategies discriminated non-overweight from overweight individuals, but did not discriminate overweight from obese individuals. In conclusion, the findings provided preliminary evidence for the acceptability and validity of the strategies. The effectiveness of the strategies for controlling the amount consumed should be further investigated, especially in overweight and obese participants.

Correlates of dietary behavior in adults: an umbrella review

Context: Multiple studies have been conducted on correlates of dietary behavior in adults, but a clear overview is currently lacking. Objective: An umbrella review, or review-of-reviews, was conducted to summarize and synthesize the scientific evidence on correlates and determinants of dietary behavior in adults. Data Sources: Eligible systematic reviews were identified in four databases: PubMed, PsycINFO, The Cochrane Library, and Web of Science. Only reviews published between January 1990 and May 2014 were included. Study Selection: Systematic reviews of observable food and dietary behavior that describe potential behavioral determinants of dietary behavior in adults were included. After independent selection of potentially relevant reviews by two authors, a total of 14 reviews were considered eligible. Data Extraction: For data extraction, the importance of determinants, the strength of the evidence, and the methodological quality of the eligible reviews were evaluated. Multiple observers conducted the data extraction independently. Data Synthesis: Social-cognitive determinants and environmental determinants (mainly the social-cultural environment) were included most often in the available reviews. Sedentary behavior and habit strength were consistently identified as important correlates of dietary behavior. Other correlates and potential determinants of dietary behavior, such as motivational regulation, shift work, and the political environment, have been studied in relatively few studies, but results are promising. Conclusions: The multitude of studies conducted on correlates of dietary behavior provides mixed, but sometimes quite convincing, evidence. However, because of the generally weak research design of the studies covered in the available reviews, the evidence for true determinants is suggestive, at best.

Using nudging and social marketing techniques to create healthy worksite cafeterias in the Netherlands: intervention development and study design

BackgroundThe worksite cafeteria is a suitable setting for interventions focusing on changing eating behavior, because a lot of employees visit the worksite cafeteria regularly and a variety of interventions could be implemented there.The aim of this paper is to describe the intervention development and design of the evaluation of an intervention to make the purchase behavior of employees in the worksite cafeteria healthier. The developed intervention called “the worksite cafeteria 2.0” consists of a set of 19 strategies based on theory of nudging and social marketing (marketing mix). The intervention will be evaluated in a real-life setting, that is Dutch worksite cafeterias of different companies and with a number of contract catering organizations.Methods/designThe study is a randomized controlled trial (RCT), with 34 Dutch worksite cafeterias randomly allocated to the 12-week intervention or to the control group. Primary outcomes are sales data of selected products groups like sandwiches, salads, snacks and bread topping. Secondary outcomes are satisfaction of employees with the cafeteria and vitality.DiscussionWhen executed, the described RCT will provide better knowledge in the effect of the intervention “the worksite cafeteria 2.0” on the purchasing behavior of Dutch employees in worksite cafeterias.Trial registrationDutch Trial register: NTR5372.

Results of a randomized controlled trial evaluating the effect of increasing package size on usage volume of peanut butter in older adults

BACKGROUND Portion and package sizes of foods generally influence energy intake in children and adults. However, little is known about this effect in older adults. This study aimed to determine the effect of increasing package size on usage volume of peanut butter in older adults. Furthermore, it is investigated whether older women and men, different age groups (<65, 65-80, and 80+), and non-overweight (BMI<25), overweight (BMI≥25) and obese (BMI>30) older adults had different responses to variation in package size. METHODS A randomized controlled trial among 205 older adults was conducted wherein participants were randomized to either the small (350 g) (n = 103) or the large (1000 g) (n = 102) package size condition. Linear regression analyses were used to determine the association between package size condition and usage volume of peanut butter on a slice of bread. Interactions of sex, age groups and BMI categories with package size were tested to investigate differences in responses to variation in package size. RESULTS Older adults spread on average 12.4 g (SD = 4.3) of peanut butter on a slice of bread when exposed to a small jar of peanut butter and 12.6 g (SD = 4.4) when exposed to a large jar of peanut butter (B = 0.15; 95%CI = -1.04 to 1.35). Interactions between sex, age groups or BMI categories with package size condition were not statistically significant. CONCLUSIONS Increased package size has no effect on usage volume of peanut butter among older adults. Older women and men, different age groups within older adults, and normal-weight, overweight and obese older adults do not respond differently to variation in package size of spreads.