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Table 4 Quality assessment and outcome of interventions

From: A systematic review of types of healthy eating interventions in preschools

Study Study design Sampling n Duration Limitations Quality1 Main target behaviour Primary and secondary outcomes
Single intervention
Bannon et al.; [16] RCT Convenience 50 3 d No controlling for internal measurement bias. ** Children: The children viewing the gain-framed and loss framed videos were significantly more likely to choose apples than controls. Among the children who saw one of the nutrition message videos, 56% chose apples rather than animal crackers; in the control condition only 33% chose apples.
Food preference questionnaire.
Healthy Food questionnaire (children circled the food they thought were healthy).
Short time between exposure and control conditions.
Snack choice between an apple or a snack
Small sample size
Short duration of intervention (3×60 s.)
Birch LL; [17] P/P Convenience 39 4 d No control * Children: Vegetable preference increased significantly from day 1 to 4.
Food preferences were assessed
No data on allocation short duration of exposure Food intake of the test vegetables The total consumption of vegetables decreased during the 4 days, but they still ate the non-preferred food item. Young children were more affected than older children by peer modelling.
Small sample size.
O’Connell et al.; [18] RCT Randomly 96 6 w   *** Children: Willingness to try new vegetables. Repeated exposure did not increase vegetable consumption.
Greater consumption by tablemates was a significant predictor of greater vegetable consumption. 1 gr. of peer intake was associated with roughly 1/5 gr. Intake among the subjects.
Harnack et al.; [19] Randomized crossover Trial Not stated 53 6 w Sampling methodology not stated. Not enough time between exposure/control conditions. ** Children: Fruit intake was significantly higher with serving style 1
Anthropometric measures
Vegetables intake did not appear to increase
Food and nutrient intake during lunch.
Small sample size
Hendy H; [20] Quasi Convenience 38 Not stated Duration not stated ** Children: The study found an effect on food acceptance, but the effect had disappeared after 1 month.
Number of bites taken of the novel foods
Food preference The children serving as peer models rated their food preferences for the novel food higher than the observers.
Mothers: Information on height, weight, age.
Leahy et al.; [21] Quasi Convenience 77 6 d No control ** Children: <decreasing the energy density of the entrée by 30% significantly decreased children’s energy intake by 25% and total lunch intake by 18%. Children consumed significantly more of the lower-energy-dense version.
Preference assessment of the two dishes
Height and weight.
Lunch intake of the two different dishes.
Child feeding questionnaire
Socio-demographic variables.
Noradilah; [22] Quasi Convenience, but randomly assigned to intervention 37 3 d The sample size is small and the duration short. Liking was assessed by parents ** Children: The liking scores were significantly higher after the intervention. Consumption of the test vegetable significantly increased from 21.58 to 28.26 on the 3rd day. The effect was especially evident among girls.
Food intake of the test vegetable
Parents: Liking of the test vegetable
A questionnaire was developed to obtain information on the usual preparation methods of vegetables, frequency of vegetables served and consumed by children at home
Ramsey; [23] Quasi Not stated 235 5 d No individual data. Short duration No control conditions Sampling conditions are not stated * Children: Food intake at lunch. The food intake was on canteen level, not at an individual level. Children’s intake of chicken nuggets was greater when they were not given a choice of nugget portion size. Demonstrating that serving larger portion sizes in preschools increase children’s intake of them.
Educational intervention
Başkale et al.; [24] RCT Convenience 115 6 w High drop-out rate (50% +). No evaluation of parent part of intervention. *** Children: Children’s nutritional knowledge increased significantly compared to control group.
Body Mass Index
Mid-upper arm circumference
Nutrition knowledge.
Healthy food consumption increase significantly in milk, yoghurt, white meat and green leafy vegetables. No anthropometric differences.
Demographic data
Food consumption of children
Cason KL; [25] P/P Convenience. 6102 24 w No control or comparison group ** Children: Subjects showed significant improvement in food identification and recognition, healthy snack identification, willingness to taste food, and frequency of fruit, vegetables, meat and dairy consumption.
Knowledge and attitude pictorial questionnaire.
Parents: Children’s eating habits and food attitudes.
Food frequency questionnaire and pictorial assessment of food likes.
Cespedes; [26] Cluster RCT Randomly 1216 5 m   **** Children: Height and weight Knowledge and attitude scores. Children showed significantly changes in knowledge and attitudes. Parents showed statistically significant, but minor changes in knowledge, attitudes and habits. More children were eutrophic after the intervention.
Nutritional status
Parental knowledge and attitudes.
Gorelick et al.; [27] RCT Convenience 187 6 w   *** Children: The outcomes were fruit identification; vegetable identification; bread identification; vegetables classification; fruit classification; matching; tooth brushing; hand washing; food preparation; food choices and there was a significant improvement over the course of the project. Older children scored higher than the younger ones.
Identification of bread, fruits and vegetables
Food classification of bread, fruits and vegetables.
Food preparation
Food choices
Hu et al.; [28] RCT Randomly 2102 10 m Educational intervention not theoretically founded **** Parents: No significant difference in anthropometrics but difference in children’s unhealthy diet related behaviours and parents attitudes and knowledge between intervention and control.
Nutrition-related eating behaviours.
Nutrition knowledge
Attitudes to the factors they considered important when arranging their children’s dietary habits. Food frequency questionnaire
Children: Height and weight.
Johnson SL; [29] Quasi Convenience 25 6 w Small sample size No control Short exposure time * Children: Compensation index based on baseline food intake data. Anthropometric data. Food intake was measured and showed that children had improved their ability to compensate their energy intake according to the energy density of food offered. The intervention did not have an effect on BMI.
Nemet; [30, 31] RCT Not stated 725 1 y Sampling methodology not stated *** Children: Weight and height. Nutritional knowledge and preferences using a photo-elicitated questionnaire. Significant increase in nutritional and physical activity knowledge and preference
Frequency of nutritional education not stated.
Significant decrease in number of overweight children.
Intervention not theoretically founded
Significant improvement in fitness
No sign in BMI percentiles, but 32% from overweight to normal weight.
At follow-up after 1 year with 206 children BMI and BMI percentiles were significantly lower in the intervention group compared to control. Nutritional knowledge and preferences remained significantly elevated in the intervention group compared to the control.
Parcel et al.; [32] Quasi Convenience 173 4 y Allocation process is missing. Lack of transparency in changes of the sample throughout the study. ** Mothers: Health values, health behaviour in the home. No evidence of effect on fruit consumption as a replacement for candy according to parent self-reporting. However, there was strong evidence of less candy eating among the health curriculum group compared to the control according to teacher observation. No evidence of increased variety in food for lunch.
Children: Health locus of control.
Preferences for health and safety behaviour
Lack of information on validation
Teachers: Observation of children regarding health and safety behaviour.
Piziak V; [33] Quasi Convenience 413 1 y No control ** Parents: Food frequency questionnaire. There was a significant increase in vegetables served outside the preschools both on weeks and in weekends.
Sampling methodology not stated
Intervention not theoretically founded
Lack of information regarding intervention group.
Sirikulchayanonta et al.; [34] Quasi Random selected school, but convenient chosen class 26 8 w Lack of information of intervention group Small sample size. * Parents: Demographic variables The use of food experience, multimedia and role models were effective in increasing F&V consumption
Family F&V vegetables consumption behaviour.
Changes in the children eating behaviour after the intervention.
Children: F&V behaviour at lunch time in respect to kinds and amounts consumed.
Witt et al.; [35] RCT Not stated 263 6 w Sampling methodology not stated. *** Children: Food consumption of F&V snacks. Strong evidence that the Color Me Healthy program increased F&V snack consumption among the intervention group compared to the control group. There was a significant increase in consumption of fruit with 20,8% and with vegetable snacks with 33,1%.
The parental data at follow-up was only at 14%, which was insufficient to make substantive conclusions. Parents: Changes in children’s F&V consumption at home.
Food frequency questionnaire
General health survey.
Multi component intervention        
Bayer et al.; [36] Cluster RCT Randomly 1609 1 y   **** Parents: Children eating habits and food frequency data were examined using a questionnaire. The program led to an increased proportion of children with high fruit and vegetable consumption after 6 months, which was sustainable with adjusted odds ratios of 1.59 (1.26: 2.01) and 1.48 (1.08:2.03) after 18 months. Subgroup analyses by gender, overweight and parental education, performed in order to assess consistency of effects, showed similar results. Prevalence of overweight and obesity as well as motoric testing results were not statistically different between intervention and control groups.
Anthropometrics (height, weight) and motoric testing of children were done at the yearly health examination offered to all children in the area of Bavaria.
Brouwer et al.; [37] RCT Randomly 16 4 m The intervention was carried out in 6 preschool, but only 3 children per class were evaluated causing a small sample size, also the children were not the same at pre and post measurement ** Children: Structured dietary observation of food intake during meals and snack time in preschools. Consumption increased with an additional ¼ serving of vegetables, despite fewer vegetables being served.
Child care centres: Demographic variables including low-income children and ethnicity of child care directors.
De Bock et al.; [38] Cluster RCT Convenience 348 6 m High dropout rate *** Children: Height, weight, waist circumference, total body fat using skinfold measurement. Children’s fruit and vegetable intakes increased significantly.
No significant changes in the consumption of water and sugared drinks were found.
Parents: Questionnaire assessing multiple domains of behaviour including
No anthropometric measurements changes were found.
Children’s’ eating behaviour and physical activity.
Food frequency questionnaire.
Socio-demographic information.
Hammond et al.; [39] RCT Convenience 123 7 m   *** Children: Interviews with children to test their familiarity. Familiarity with and stated willingness to eat 16 tested foods increased significantly.
Parents: Demographic variables
Children’s willingness-to-eat. Mentioning of exposure of foods in KG when requesting food at home more than doubled (reported by parents)
Changes in the child’s dietary habits over the school year.
Hoffman et al.; [40] RCT Convenience 297 1 y Demographic difference between intervention and control group. *** Children: Awareness of the intervention No difference in F&V preferences
F&V preferences Increase in fruit and vegetable intake at year 1, but at year 2 a difference was only found on fruit intake.
Weighed plate waste during 3 lunches in the preschool cafeteria.
Height and weight
Caregiver/parents: Demographic variables
Vereecken et al.; [41] RCT Convenience 476 6 m Response rate is low 33% *** Parents: Food frequency questionnaire on their children’s general food consumption. Increased fresh fruit intake among the intervention children, but the effect was only significant among parental reported fruit consumption. The increase was due to more available fruit at school.
Socio-demographic information
Questions relating to the school food policy. Teachers: Registration of food available for consumption.
Williams et al.; [42] Quasi Convenience 787 6 m No information about the allocation process. *** Children: Dietary intake by observation during school and by interviewing the parents. Very strong evidence of a decreased relative risk of elevated cholesterol levels among children with elevated cholesterol at baseline in both food service modification groups. Furthermore, strong evidence of a decrease in total cholesterol in the two food service modification groups compared to the control group.
Weight and height
  1. *See quality rating scheme in Table 2. Indicating: the the strength of the studies: *Weak, ** Moderate, *** Strong and **** Very strong.