What is the question? 

• The question is: What is the relationship between complementary feeding and growth, body composition, and risk of obesity? The populations of interest for this question include infants and young children at intervention or exposure and infants, young children, children, adolescents, adults, and older adults at outcome. 

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 existing reviews that were conducted as part of the Pregnancy and Birth to 24 Months Project. 

What is the answer to the question? 

Timing of introduction of specific types of complementary foods and beverages

• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to 100% juice and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available. 
• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to fruit and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available. 
• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to vegetables and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available.
• Introducing grains at or before age 4 months is associated with higher BMI z-score during childhood. This conclusion statement is based on evidence graded as limited. 
• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to grains and body composition and risk of obesity during childhood because there is not enough evidence available. 
• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to foods from the protein foods group and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency in the body of evidence. 
• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to the dairy food group and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available, and the evidence that is available has substantial concerns with consistency. 
• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to sugar-sweetened beverages and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency in the body of evidence. 
• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to food sources of added sugars and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available. 

Types and amounts of complementary foods and beverages

• A conclusion statement cannot be drawn about the relationship between 100% juice consumption by infants and young children, up to age 24 months, and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency and precision in the body of evidence. 
• Fruit consumption by infants and young children, up to age 24 months, is not associated with unfavorable outcomes related to growth patterns during childhood. This conclusion statement is based on evidence graded as limited. 
• A conclusion statement cannot be drawn about the relationship between fruit consumption by infants and young children, up to age 24 months, and body composition and risk of obesity during childhood because there is not enough evidence available. 
• Vegetable consumption by infants and young children, up to age 24 months, is not associated with unfavorable outcomes related to growth patterns during childhood. This conclusion statement is based on evidence graded as limited. 
• A conclusion statement cannot be drawn about the relationship between vegetable consumption by infants and young children, up to age 24 months, and body composition and risk of obesity during childhood because there is not enough evidence available. 
• Grains consumption by infants and young children, from age 6 months up to age 24 months, is not associated with unfavorable outcomes related to growth patterns and risk of obesity during childhood. This conclusion statement is based on evidence graded as limited. 
• A conclusion statement cannot be drawn about the relationship between grains consumption by infants and young children, from age 6 months up to age 24 months, and outcomes related to body composition during childhood because there is not enough evidence available. 
• A conclusion statement cannot be drawn about the relationship between consumption of protein foods as a food group by infants and young children, up to age 24 months, and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency and directness in the body of evidence. 
• A conclusion statement cannot be drawn about the relationship between dairy consumption by infants and young children, up to age 24 months, and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency in the body of evidence. 
• Sugar-sweetened beverage consumption by infants, children, and adolescents is associated with unfavorable growth patterns and body composition, and higher risk of obesity in childhood up to early adulthood. This conclusion statement is based on evidence graded as moderate. 
• A conclusion statement cannot be drawn about the relationship between consumption of food sources of added sugars by infants and young children, up to age 24 months, and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available.

How up-to-date is this systematic review?

• Conclusion statements from this review are based on articles published between January 1980 and May 2023.

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 the USDA Nutrition Evidence Systematic Review (NESR) team to answer the following question: What is the relationship between complementary feeding and growth, body composition, and risk of obesity? This review is an update to existing reviews that were conducted as part of the Pregnancy and Birth to 24 Months Project. 

Methods 

• The Committee conducted a systematic review using the methodology of the USDA NESR team. The Committee first developed a protocol. The interventions/exposures were first introduction of a specific type of complementary food or beverage (fruit, including 100% fruit juice, vegetables, grains, protein foods, dairy and fortified soy alternatives, and food/beverage sources of added sugars) and types and amounts of complementary foods and beverages (fruit, including 100% fruit juice, vegetables, grains, protein foods, dairy and fortified soy alternatives, and food/beverage sources of added sugars) in infants and young children (birth up to 24 months); the comparators were different timing of the first introduction of a specific type of complementary food or beverage and different amount of the same complementary food or beverage or different type of complementary food or beverage; and the outcomes were measures of growth in infants, young children, children, adolescents, body composition in infants, young children, children, adolescents, adults, older adults, and risk of obesity in children, adolescents, adults, older adults. 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 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 randomized or non-randomized controlled trials that were not designed to examine growth, body composition, and/or risk of obesity as a primary outcome. 
• NESR librarians conducted a literature search in PubMed, Embase, CINAHL, and Cochrane to identify articles published between July 2016 and May 2023. 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 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, from all included articles identified in the updated literature search and from the existing review, according to the synthesis plan, 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 

Timing of the first introduction: 100% juice 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to 100% juice and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available. (Grade: Grade Not Assignable) 

Summary of the evidence 

• One article examined timing of the first introduction of 100% juice and growth, body composition, and risk of obesity. This study was a prospective cohort study. 
• There was not enough evidence available to draw a conclusion statement. 

Timing of the first introduction: fruit 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to fruit and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Three articles examined timing of the first introduction of fruit and growth, body composition, and risk of obesity. All 3 were prospective cohort studies. 
• There was not enough evidence available to draw a conclusion statement. 

Timing of the first introduction: vegetables 

Conclusion statement and grade

• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to vegetables and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Three articles examined timing of the first introduction of vegetables and growth, body composition, and risk of obesity. All 3 were prospective cohort studies. 
• There was not enough evidence available to draw a conclusion statement. 

Timing of the first introduction: grains 

Conclusion statement and grade 

• Introducing grains at or before age 4 months is associated with higher BMI z-score during childhood. This conclusion statement is based on evidence graded as limited. (Grade: Limited) 

Summary of the evidence 

• Six articles examined timing of the first introduction of grains and growth. All 6 were prospective cohort studies. 
• There was some inconsistency in the statistical significance of results, however, the direction of the associations were primarily consistent. 
• Effect estimates were small. Few studies met inclusion criteria.
• Few studies were designed and conducted well.
• The populations, exposures, comparators, and outcomes that were examined directly represented those of interest in this review. 
• The evidence may not apply to the U.S. population. 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to grains and body composition and risk of obesity during childhood because there is not enough evidence available. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Three articles examined timing of the first introduction of grains and body composition and risk of obesity. All 3 were prospective cohort studies. 
• There was not enough evidence available to draw a conclusion statement. 

Timing of the first introduction: protein foods 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to foods from the protein foods group and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency in the body of evidence. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Four articles examined timing of the first introduction of foods from the protein foods group and growth, body composition, and risk of obesity. All 4 were prospective cohort studies. 
• A conclusion statement was not drawn because the exposures were too different across studies. 

Timing of the first introduction: dairy and fortified soy alternatives 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to the dairy food group and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available, and the evidence that is available has substantial concerns with consistency. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Thirteen articles examined timing of the first introduction of dairy and growth, body composition, and risk of obesity. All 13 were prospective cohort studies. 
• A conclusion statement was not drawn because the exposures and comparators were too different across studies. 

Timing of the first introduction: sugar-sweetened beverages 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to sugar-sweetened beverages and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency in the body of evidence. (Grade: Grade Not Assignable) 

Summary of the evidence

• Nine articles examined timing of the first introduction of sugar-sweetened beverages and growth, body composition, and risk of obesity. All 9 were prospective cohort studies.
• A conclusion statement was not drawn because the exposures, comparators, and age at outcome assessment were too different across studies. 

Timing of the first introduction: food sources of added sugars 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between the age when infants and young children, up to age 24 months, are introduced to food sources of added sugars and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available. (Grade: Grade Not Assignable) 

Summary of the evidence 

• One article examined timing of the first introduction of food sources of added sugars and growth, body composition, and risk of obesity. This study was a prospective cohort study. 
• There was not enough evidence available to draw a conclusion statement. 

Types and amounts: 100% juice 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between 100% juice consumption by infants and young children, up to age 24 months, and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency and precision in the body of evidence. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Four articles examined 100% juice consumption and growth, body composition, and risk of obesity. All 4 were prospective cohort studies.
• A conclusion statement was not drawn because few studies met inclusion criteria and the results and outcomes were too different across studies. 

Types and amounts: fruit 

Conclusion statement and grade 

Fruit consumption by infants and young children, up to age 24 months, is not associated with unfavorable outcomes related to growth patterns during childhood. This conclusion statement is based on evidence graded as limited. (Grade: Limited) 

Summary of the evidence 

• Five articles examined fruit consumption and growth. All 5 were prospective cohort studies. 
• Results were similar across studies, reporting primarily null associations. 
• Variation around the effect estimates were wide across studies. Few studies met inclusion criteria. 
• Few studies were designed and conducted well. 
• The populations, exposures, comparators, and outcomes that were examined directly represented those of interest in this review. 
• The evidence may not apply to the U.S. population. 

Conclusion statement and grade

• A conclusion statement cannot be drawn about the relationship between fruit consumption by infants and young children, up to age 24 months, and body composition and risk of obesity during childhood because there is not enough evidence available. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Three articles examined fruit consumption and body composition and risk of obesity. All 3 were prospective cohort studies. 
• There was not enough evidence available to draw a conclusion statement. 

Types and amounts: vegetables 

Conclusion statement and grade 

• Vegetable consumption by infants and young children, up to age 24 months, is not associated with unfavorable outcomes related to growth patterns during childhood. This conclusion statement is based on evidence graded as limited. (Grade: Limited) 

Summary of the evidence 

• Five articles examined vegetable consumption and growth. All 5 were prospective cohort studies. 
• Results were similar across studies, reporting primarily null associations. 
• Few studies met inclusion criteria. 
• Many studies had a risk of bias due to confounding, missing data, and selection of the reported result. 
• The populations, exposures, comparators, and outcomes that were examined directly represented those of interest in this review. 
• The evidence may not apply to the U.S. population. 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between vegetable consumption by infants and young children, up to age 24 months, and body composition and risk of obesity during childhood because there is not enough evidence available. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Three articles examined vegetable consumption and body composition and risk of obesity. All 3 were prospective cohort studies. 
• There was not enough evidence available to draw a conclusion statement. 

Types and amounts: grains 

Conclusion statement and grade 

• Grains consumption by infants and young children, from age 6 months up to age 24 months, is not associated with unfavorable outcomes related to growth patterns and risk of obesity during childhood. This conclusion statement is based on evidence graded as limited. (Grade: Limited) 

Summary of the evidence 

• Fourteen articles examined grains consumption and growth and risk of obesity. Three were randomized controlled trials and 11 were prospective cohort studies. 
• Studies were somewhat inconsistent in the significance and direction of findings, with several studies reporting null findings. 
• The size of study groups was too small in some studies. Few studies reported power. 
• Few studies were designed and conducted well. 
• The populations, interventions/exposures, comparators and outcomes that were examined primarily directly represented those of interest in this review, but a few of the interventions/exposures and comparators did not. 
• The evidence may not apply to the U.S. population. 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between grains consumption by infants and young children, from age 6 months up to age 24 months, and outcomes related to body composition during childhood because there is not enough evidence available. (Grade: Grade Not Assignable) 

Summary of the evidence 

• One article examined grains consumption and body composition. This study was a prospective cohort study. 
• There was not enough evidence available to draw a conclusion statement. 

Types and amounts: protein foods 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between consumption of protein foods as a food group by infants and young children, up to age 24 months, and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency and directness in the body of evidence. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Thirteen articles examined consumption of protein foods and growth, body composition, and risk of obesity. Three were randomized controlled trials, 2 were cluster-randomized controlled trials, and 8 were prospective cohort studies. 
• A conclusion statement was not drawn because the interventions/exposures and comparators were too different across studies and the interventions/exposures that were examined did not directly represent those of interest in this review. 

Types and amounts: dairy and fortified soy alternatives 

Conclusion statement and grade 

• A conclusion statement cannot be drawn about the relationship between dairy consumption by infants and young children, up to age 24 months, and outcomes related to growth patterns, body composition, and risk of obesity during childhood because of substantial concerns with consistency in the body of evidence. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Fourteen articles examined dairy consumption and growth, body composition, and risk of obesity. Four were randomized controlled trials, 2 were non-randomized controlled trials, and 8 were prospective cohort studies. 
• A conclusion statement was not drawn because the ages at intervention/exposure, comparators, and outcomes were too different across studies. 

Types and amounts: sugar-sweetened beverages 

Conclusion statement and grade 

• Sugar-sweetened beverage consumption by infants, children, and adolescents is associated with unfavorable growth patterns and body composition, and higher risk of obesity in childhood up to early adulthood. This conclusion statement is based on evidence graded as moderate. (Grade: Moderate) 

Summary of the evidence 

• Seventeen articles examined sugar-sweetened beverage consumption and growth, body composition, and risk of obesity. All 17 were prospective cohort studies. 
• The articles were synthesized as part of the systematic review with meta-analysis on sugar-sweetened beverages and growth, body composition, and risk of obesity across the lifespan to avoid duplication of effort. 

Types and amounts: food sources of added sugars 

Conclusion statement and grade

• A conclusion statement cannot be drawn about the relationship between consumption of food sources of added sugars by infants and young children, up to age 24 months, and outcomes related to growth patterns, body composition, and risk of obesity during childhood because there is not enough evidence available. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Five articles examined consumption of food sources of added sugars and growth, body composition, and risk of obesity. All 5 were prospective cohort studies. 
• There was not enough evidence available to draw a conclusion statement.

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Suggested citation: Fisher JO, Abrams SA, Andres A, Byrd-Bredbenner C, Deierlein AL, Eicher-Miller HA, Odoms-Young A, Palacios C, Bahnfleth C, Kim JH, Higgins M, Nevins J, Butera G, Terry N, Obbagy J. Complementary Feeding and Growth, Body Composition, and Risk of Obesity: 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.SR18