ABSTRACT
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 consumption of dietary patterns with varying amounts of ultra-processed foods and growth, body composition, and risk of obesity?
Methods
The Committee conducted a systematic review using the methodology of the USDA NESR team. The Committee first developed a protocol. The intervention/exposure and comparators for all populations were consumption of a dietary pattern with ultra-processed foods (UPF) compared to a dietary pattern without UPF and different adherence to/consumption levels of the same dietary pattern that reflect differences in the amount of UPF. The outcomes were measures of growth, body composition, and risk of obesity in all populations. Additional criteria were established to include: a) randomized or non-randomized controlled trial, prospective or retrospective cohort, or nested case-control designs, b) published in English in peer-reviewed journals, c) studies in countries classified as high or very high level of human development, and d) participants with a range of health statuses. The review excluded studies that exclusively enrolled participants who were being treated for a disease.
NESR librarians performed the literature search in PubMed, Embase, CINAHL, and Cochrane to identify articles published between January 2000 and January 2024. Two NESR analysts independently screened all electronic results and the reference lists of included articles based on the pre-determined criteria. 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 synthesized the eligible evidence from the existing review and the new evidence 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
Infants and Young Children up to Age 24 Months
Conclusion statement* and grade: A conclusion statement cannot be drawn about the relationship between dietary patterns consumed by infants and young children up to age 24 months with varying amounts of UPF and growth, body composition, and risk of obesity because of substantial concerns with consistency and directness in the body of evidence. (Grade Not Assignable)
Summary of evidence:
• Five articles from prospective cohort study designs met inclusion for this review in infants and young children.
• The 2025 Committee was not able to draw a conclusion due to critical limitations in the body of evidence.
Children and Adolescents
Conclusion statement and grade: Dietary patterns consumed by children and adolescents with higher amounts of foods classified as UPF are associated with greater adiposity (fat mass, waist circumference, BMI) and risk of overweight. This conclusion statement is based on evidence graded as limited. (Grade: Limited)
Summary of evidence:
• Twenty-five articles met inclusion for this review in children and adolescents. All 25 articles were prospective cohort studies.
• The direction of results was similar across studies, but effect size differed.
• The size of study groups was small and variance around effect estimates was wide across studies.
• Few studies were designed and conducted well.
• The populations and outcome measures represented those of interest in the review, but most dietary patterns examined did not.
• The evidence applies to the U.S. population, except the types and amounts of UPF examined may not be applicable.
Adults and Older Adults
Conclusion statement and grade: Dietary patterns consumed by adults and older adults with higher amounts of foods classified as UPF are associated with greater adiposity (fat mass, waist circumference, BMI) and risk of obesity and/or overweight. This conclusion statement is based on evidence graded as limited. (Grade: Limited)
Summary of evidence:
• Sixteen articles met inclusion for this review in adults and older adults. Fifteen articles were prospective cohort study designs and one article was a randomized controlled trial.
• The direction of results was similar across studies, but effect size differed.
• The size of study groups was small and variance around effect estimates was wide across studies.
• Few studies were designed and conducted well.
• The populations and outcome measures represented those of interest in the review, but most dietary patterns examined did not.
• The evidence applies to the U.S. population, except the types and amounts of UPF examined may not be applicable
Pregnancy
Conclusion statements and grades: A conclusion statement cannot be drawn about the relationship between dietary patterns consumed during pregnancy with varying amounts of UPF and gestational weight gain because there is not enough evidence available. (Grade Not Assignable).
Summary of evidence: One article from a prospective cohort study design met inclusion criteria for this review in individuals during pregnancy. The 2025 Committee was not able to draw a conclusion due to not enough evidence being available.
Postpartum
Conclusion statements and grades: A conclusion statement cannot be drawn about the relationship between dietary patterns consumed during postpartum with varying amounts of UPF and postpartum weight change because there is not enough evidence available. (Grade Not Assignable).
Summary of evidence: Two articles from prospective cohort study designs met inclusion criteria for this review in individuals during postpartum. The 2025 Committee was not able to draw a conclusion due to not enough evidence being available.
* A conclusion statement is carefully constructed, based on the evidence reviewed, to answer the systematic review question. A conclusion statement does not draw implications and should not be interpreted as dietary guidance.