What is the question?

• The question is: What is the relationship between repeated exposure to foods and food acceptance? The population of interest for this question include infants and young children birth to 24 months and children 2 to 6 years.

Why was this question asked?

• This systematic review was conducted by the 2025 Dietary Guidelines Advisory Committee as part of the process to develop the Dietary Guidelines for Americans, 2025-2030.

How was this question answered?

• The Committee conducted a systematic review to answer this question with support from the USDA Nutrition Evidence Systematic Review team. This review updated an existing review that was conducted as part of the Pregnancy and Birth to 24 Months Project (P/B-24 Project).

What is the answer to the question?

Infants and young children (birth to 24 months)

• Repeated taste exposure to a single or multiple novel or familiar vegetable(s) is likely to increase acceptance of the target vegetable(s) by infants and young children ages 4 to 24 months. This conclusion statement is based on evidence graded as moderate.
• Repeated taste exposure to a single fruit is likely to increase acceptance of the target fruit by infants and young children ages 4 to 24 months. This conclusion statement is based on evidence graded as moderate.
• Repeated taste exposure to a vegetable is likely to increase acceptance of a different vegetable, but not a fruit by infants and young children ages 4 to 24 months. This conclusion statement is based on evidence graded as moderate.
• Repeated taste exposure to a fruit may increase acceptance of a different fruit, but not a vegetable, by infants and young children ages 4 to 24 months. This conclusion statement is based on evidence graded as limited.
• A conclusion statement cannot be drawn about the effect of repeated non-taste exposure, either alone or together with taste exposure, on food acceptance by infants and young children ages 4 to 24 months because there are substantial concerns with consistency and directness in the body of evidence. ​

Children (2 to 6 years)

• Repeated taste exposure to a single or multiple novel or familiar vegetable(s) is likely to increase acceptance of the target vegetable(s) by children ages 2 to 6 years. This conclusion statement is based on evidence graded as moderate.
• A conclusion statement cannot be drawn about the effect of repeated taste exposure to fruit(s) on acceptance of target fruit(s) by children ages 2 to 6 years because there is no evidence available.
• Repeated taste exposure to a target vegetable may increase acceptance of a different vegetable by children ages 2 to 6 years. This conclusion statement is based on evidence graded as limited.
• A conclusion statement cannot be drawn about the effect of repeated taste exposure to a target fruit on acceptance of a different fruit by children ages 2 to 6 years because there is no evidence available.
• Repeated non-taste exposure alone or together with taste exposure to a target fruit or vegetable increases acceptance, specifically willingness to try, of the target fruit or vegetable by children ages 2 to 6 years. This conclusion statement is based on evidence graded as moderate.

How up-to-date is this systematic review?

• Conclusion statements from this review are based on articles published between January 1980 and May 2023 (infants and young children) and January 2000 and May 2023 (children). 

Background

• This systematic review was conducted by the 2025 Dietary Guidelines Advisory Committee as part of the process to develop the Dietary Guidelines for Americans, 2025-2030. The U.S. Departments of Health and Human Services (HHS) and Agriculture (USDA) appointed the 2025 Dietary Guidelines Advisory Committee (Committee) in January 2023 to review evidence on high priority scientific questions related to diet and health. Their review forms the basis of their independent, science-based advice and recommendations to HHS and USDA, which is considered as the Departments develop the next edition of the Dietary Guidelines. As part of that process, the Committee conducted a systematic review with support from USDA’s Nutrition Evidence Systematic Review (NESR) team to answer the following question: What is the relationship between repeated exposure to foods and food acceptance? This review is an update to an existing review that was conducted as part of the Pregnancy and Birth to 24 Months Project (P/B-24 Project).

Methods

• The Committee conducted a systematic review using the methodology of the USDA NESR team. The Committee first developed a protocol. The intervention/exposure was repeated exposure to food or food-type among infants and young children (birth to 24 months) and children (2 to 6 years), the comparators were pre/exposure versus post-exposure (within subject), no exposure versus exposure (between subjects) and taste exposure versus non-taste exposure, and the outcomes were measures of food acceptance of the exposed food in infants, young children, or school-aged children. Additional inclusion criteria were established for the following study characteristics: a) use randomized or non-randomized controlled trial, prospective or retrospective cohort, or nested case-control/other study designs, b) be published in English in peer-reviewed journals, c) be from countries classified as high or very high on the Human Development Index, and d) enroll participants with a range of health statuses. The review excluded: multicomponent interventions in which the isolated effect of repeated food exposure on food acceptance was not provided or could not be determined due to multiple components, food or flavor exposure in utero or via breastmilk, and interventions assessing exposure to taste and/or flavor (e.g., salty, bitter, sweet) versus food.
• NESR librarians conducted a literature search in PubMed, Embase, CINAHL, Scopus and Cochrane to identify articles published between January 1980 and May 2023 (infants and young children) and January 2000 and May 2023 (children). Two NESR analysts independently screened all electronic results and the reference lists of included articles based on the pre-determined criteria. The results of this search were combined with eligible included articles from the existing review.
• NESR analysts extracted data, from each included article, with a second analyst verifying accuracy of the extraction. Two NESR analysts independently conducted a formal risk of bias assessment, by study design, for each included article, then reconciled any differences in the assessment. The Committee qualitatively synthesized the evidence, considering all articles, both those from the existing review and those identified in the updated literature search with attention given to the overarching themes or key concepts from the findings, similarities and differences between studies, and factors that may have affected the results. The Committee developed conclusion statements and graded the strength of evidence based on its consistency, precision, risk of bias, directness and generalizability.

Results

Infants and young children (birth to 24 months)

Conclusion statement and grade

• Repeated taste exposure to a single or multiple novel or familiar vegetable(s) is likely to increase acceptance of the target vegetable(s) by infants and young children ages 4 to 24 months. This conclusion statement is based on evidence graded as moderate. (Grade: Moderate)

Summary of the evidence

• Thirteen articles (12 independent studies) examined repeated taste exposure to vegetable(s) and acceptance of the target vegetable by infants and young children. Ten studies were randomized controlled trials and 2 were non-randomized controlled trials.  
• The direction of results and size of effects were similar across studies.  
• The size of the study groups was small in most studies
• The populations, exposures and outcomes that were examined directly represent those of interest in this review, but some comparators did not.

Conclusion statement and grade

• Repeated taste exposure to a single fruit is likely to increase acceptance of the target fruit by infants and young children ages 4 to 24 months. This conclusion statement is based on evidence graded as moderate. (Grade: Moderate)

Summary of the evidence

• Five articles (4 independent studies) examined repeated taste exposure to fruit and acceptance of the target fruit by infants and young children. Three studies were randomized controlled trials and 1 was a non-randomized controlled trial.  
• The direction of results was similar across studies, but the effect size differed.
• The size of study groups was small in most studies.  
• The populations, exposures and outcomes that were examined directly represent those of interest in this review, but some comparators did not.
• Most studies were designed and conducted well.  
• The populations that were examined do not directly represent those of interest in this review.

Conclusion statement and grade

• Repeated taste exposure to a vegetable is likely to increase acceptance of a different vegetable, but not a fruit by infants and young children ages 4 to 24 months. This conclusion statement is based on evidence graded as moderate. (Grade: Moderate)

Summary of the evidence

• Twelve articles (11 independent studies) examined repeated taste exposure to a vegetable and acceptance of a different vegetable or fruit by infants and young children. Ten studies were randomized controlled trials and 1 was a non-randomized controlled trial.  
• The direction of results and size of effects were similar across studies.
• The size of the study groups was small in some studies.
• The populations, exposures, comparators and outcomes that were examined directly represent those of interest in this review.
• Some studies were designed and conducted well.
• The populations that were examined do not directly represent those of interest in this review.

Conclusion statement and grade

• Repeated taste exposure to a fruit may increase acceptance of a different fruit, but not a vegetable, by infants and young children ages 4 to 24 months. This conclusion statement is based on evidence graded as limited. (Grade: Limited)

Summary of the evidence

• Three studies examined repeated taste exposure to a fruit and acceptance of a different fruit or vegetable by infants and young children. Two studies were randomized controlled trials and 1 was a non-randomized controlled trial.  
• The direction of results and size of effects were different across studies.  
• The size of study groups was small across studies.
• The populations, exposures, comparators and outcomes that were examined directly represent those of interest in this review.
• Some studies were designed and conducted well.
• The populations that were examined do not directly represent those of interest in this review.

Conclusion statement and grade

• A conclusion statement cannot be drawn about the effect of repeated non-taste exposure, either alone or together with taste exposure, on food acceptance by infants and young children ages 4 to 24 months because there are substantial concerns with consistency and directness in the body of evidence. ​(Grade: Grade Not Assignable)

Summary of the evidence

• Six articles (5 independent studies) examined repeated non-taste exposure and food acceptance by infants and young children. Four studies were randomized controlled trials and 1 was a non-randomized controlled trial.  
• The direction of results and size of effects were different across studies.  
• The size of study groups was small across studies.
• The populations and outcomes that were examined directly represent those of interest in this review, but the exposures and comparators do not. 
• Some studies were designed and conducted well.
• The populations that were examined do not directly represent those of interest in this review.

Children (2 to 6 years)

Conclusion statement and grade

• Repeated taste exposure to a single or multiple novel or familiar vegetable(s) is likely to increase acceptance of the target vegetable(s) by children ages 2 to 6 years. This conclusion statement is based on evidence graded as moderate. (Grade: Moderate)

Summary of the evidence

• Fifteen studies examined repeated taste exposure to a vegetable and acceptance of the target vegetable by children. Fourteen studies were randomized controlled trials and 1 was a non-randomized controlled trial.  
• The direction of results and size of effects were similar across studies.  
• The size of the study groups was large across studies.
• The populations, exposures and outcomes that were examined directly represent those of interest in this review, but some comparators did not.
• Most studies were designed and conducted well. 
• The populations that were examined do not directly represent those of interest in this review.  

Conclusion statement and grade

• A conclusion statement cannot be drawn about the effect of repeated taste exposure to fruit(s) on acceptance of target fruit(s) by children ages 2 to 6 years because there is no evidence available. (Grade: Grade Not Assignable)

Summary of the evidence

• There were 0 studies that examined repeated taste exposure to a fruit and acceptance of the target fruit by children.
• The 2025 Committee was not able to draw a conclusion due to not enough evidence being available.

Conclusion statement and grade

• Repeated taste exposure to a target vegetable may increase acceptance of a different vegetable by children ages 2 to 6 years. This conclusion statement is based on evidence graded as limited. (Grade: Limited)

Summary of the evidence

• Six studies examined repeated taste exposure to a vegetable and acceptance of a different vegetable by children. All 6 studies were randomized controlled trials.   
  The direction of results and size of effects were different across studies.  
• The size of the study groups was small across studies.
• The populations, exposures and outcomes that were examined directly represent those of interest in this review, but some comparators did not. 
• Some studies were designed and conducted well.
• The populations that were examined do not directly represent those of interest in this review.  

Conclusion statement and grade

• A conclusion statement cannot be drawn about the effect of repeated taste exposure to a target fruit on acceptance of a different fruit by children ages 2 to 6 years because there is no evidence available. (Grade: Grade Not Assignable)

Summary of the evidence

• There were 0 studies that examined repeated taste exposure to fruit and acceptance of a different fruit by children.
• The 2025 Committee was not able to draw a conclusion due to not enough evidence being available.

Conclusion statement and grade

• Repeated non-taste exposure alone or together with taste exposure to a target fruit or vegetable increases acceptance, specifically willingness to try, of the target fruit or vegetable by children ages 2 to 6 years. This conclusion statement is based on evidence graded as moderate. (Grade: Moderate)

Summary of the evidence

• Five studies examined repeated non-taste exposure and food acceptance by children.
• Four studies were randomized controlled trials and 1 was a non-randomized controlled trial.  
• The direction of results was similar across most studies, but the size of effect differed.  
• The size of the study groups was small in most studies.
• The populations, exposures and outcomes that were examined directly represent those of interest in this review, but some comparators did not.
• Some studies were designed and conducted well.
• The populations that were examined do not directly represent those of interest in this review.  

Download Now

Suggested citation: Fisher JO, Eicher-Miller HA, Odoms-Young A, Palacios C, Abrams SA, Andres A, Byrd-Bredbenner C, Deierlein A, Lawless M, Momin S, Spahn J, Butera G, Higgins M, Terry N, Obbagy J. Repeated Exposure to Foods and Food Acceptance: A Systematic Review. November 2024. U.S. Department of Agriculture, Food and Nutrition Service, Center for Nutrition Policy and Promotion, Nutrition Evidence Systematic Review. Available at: https://doi.org/10.52570/NESR.DGAC2025.SR06