Scientific Questions
The 2025 Dietary Guidelines Advisory Committee (Committee) is examining a list of prioritized scientific questions, informed by the proposed list of scientific questions identified by HHS and USDA. The Committee divided into subcommittees to conduct its evidence review. Each question is addressed by one subcommittee; however, some topics (like dietary patterns) and populations (like older adults) are addressed in multiple questions and sometimes by more than one subcommittee. The Committee is working collectively across subcommittees as it examines the evidence in preparation for developing its scientific report.
The Committee is using three scientific approaches to examine the evidence: data analysis, food pattern modeling, and systematic reviews. The protocol – or plan – for how each question will be examined, can be found on the NESR’s website, for questions being answered using systematic review, or on DietaryGuidelines.gov for questions being answered using food pattern modeling. Protocols are now available for the majority of questions the Committee will examine during its evidence review. The few remaining protocols will be posted after they are discussed by the Committee at a public meeting. The data analysis plan that outlines the process, strategy, and analyses is available.
In accordance with the Federal Advisory Committee Act, the Committee will have up to two years to complete its work, and this time limit may impact the number of questions that the Committee is able to address during its tenure. Updates about the Committee’s work and progress on answering the questions below will be provided during its meetings. Visit the Attend a Meeting page to view Committee meetings and access more information about the Committee’s work, including meeting slides and summaries.
Subcommittee 1: Dietary Patterns and Specific Dietary Pattern Components Across Life Stages |
Systematic Review Questions: |
Dietary Patterns |
| What is the relationship between dietary patterns consumed and growth, body composition, and risk of obesity? |
| What is the relationship between dietary patterns consumed and risk of cardiovascular disease? |
| What is the relationship between dietary patterns consumed and risk of type 2 diabetes? |
| What is the relationship between consumption of dietary patterns with varying amounts of ultra-processed foods and growth, body composition, and risk of obesity? |
| What is the relationship between dietary patterns consumed and risk of breast cancer? |
| What is the relationship between dietary patterns consumed and risk of colorectal cancer? |
| What is the relationship between dietary patterns consumed and risk of prostate cancer? |
| What is the relationship between dietary patterns consumed and risk of cognitive decline, dementia, and Alzheimer's disease? |
| What is the relationship between dietary patterns consumed and risk of depression? |
| What is the relationship between dietary patterns consumed and bone health? |
Beverages |
| What is the relationship between beverage patterns consumed and growth, body composition, and risk of obesity? |
| What is the relationship between dairy milk and milk alternative consumption and growth, body composition, and risk of obesity? |
| What is the relationship between 100% juice consumption and growth, body composition, and risk of obesity? |
| What is the relationship between sugar-sweetened beverage consumption and growth, body composition, and risk of obesity? |
| What is the relationship between low- and no-calorie sweetened beverage consumption and growth, body composition, and risk of obesity? |
| What is the relationship between coffee and/or tea consumption and growth, body composition, and risk of obesity? |
| What is the relationship between dairy milk and milk alternative consumption and risk of type 2 diabetes? |
| What is the relationship between 100% juice consumption and risk of type 2 diabetes? |
| What is the relationship between sugar-sweetened beverage consumption and risk of type 2 diabetes? |
| What is the relationship between low- and no-calorie sweetened beverage consumption and risk of type 2 diabetes? |
| What is the relationship between coffee and/or tea consumption and risk of type 2 diabetes? |
Food Sources |
| What is the relationship between food sources of saturated fat consumed and risk of cardiovascular disease? |
Subcommittee 2: Diet in Pregnancy and Birth through Adolescence |
Systematic Review Questions: |
| What is the relationship between dietary patterns consumed during pregnancy and risk of hypertensive disorders of pregnancy? |
| What is the relationship between dietary patterns consumed during pregnancy and risk of gestational diabetes mellitus? |
| What is the relationship between repeated exposure to foods and food acceptance? |
| What is the relationship between complementary feeding and growth, body composition, and risk of obesity? |
| What is the relationship between parental and caregiver feeding styles and practices during childhood and adolescence and growth, body composition, and risk of obesity? |
| What is the relationship between parental and caregiver feeding styles and practices during childhood and adolescence and consuming a dietary pattern that is aligned with the Dietary Guidelines for Americans? |
| What is the relationship between dietary patterns consumed during pregnancy and gestational age at birth? |
| What is the relationship between dietary patterns consumed during pregnancy and birth weight? |
Subcommittee 3: Food Pattern Modeling and Data Analysis |
Food Pattern Modeling Questions: |
| Should foods and beverages with lower nutrient density (i.e., those with added sugars, saturated fat, and sodium) contribute to item clusters, representative foods, and therefore the nutrient profiles for each food group and subgroup used in modeling the USDA Dietary Patterns? |
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For each food group, what is the impact on the nutrient adequacy of the USDA Dietary Patterns if: (1) the recommended daily or weekly quantity of the food group or subgroup is modified (e.g., between a range of 0 to a number above the current recommendation) and (2) if the proportion coming from each subgroup within a food group is modified? If the nutrient adequacy of the dietary patterns is affected by these changes in food groups and subgroups, what other changes to the USDA Dietary Patterns could help meet nutrient adequacy for each life stage (e.g., toddlers, older adults, individuals who are pregnant or lactating, adolescents)? Specific flexibilities of interest include:
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| What quantities of foods and beverages lower in nutrient density can be accommodated in the USDA Dietary Patterns while meeting nutrient recommendations within calorie levels? |
| Do simulated diets that meet the updated USDA Dietary Patterns and reflect variation in dietary intakes achieve nutrient adequacy? |
Data Analysis Questions: |
| What are the current patterns of food and beverage intake? |
| What are the current intakes of food groups, nutrients, and dietary components? |
| Which nutrients and/or dietary components present a substantial public health concern because of underconsumption or overconsumption? |
| What is the current prevalence of nutrition-related chronic health conditions? |
Subcommittee 4: Strategies for Individuals and Families Related to Diet Quality and Weight Management |
Systematic Review Questions: |
| What is the relationship between frequency of meals and/or snacks and growth, body composition, and risk of obesity? |
| What is the relationship between frequency of meals and/or snacks and energy intake? |
| What is the relationship between frequency of meals and/or snacks and consuming a dietary pattern that is aligned with the Dietary Guidelines for Americans? |
| What is the relationship between portion size and growth, body composition, and risk of obesity? |
| What is the relationship between portion size and energy intake? |
*Home food availability and cultural and traditional foods are other strategies being explored.