Every 5 years, the US Department of Agriculture and Department of Health and Human Services convene the Dietary Guidelines Advisory Committee to review existing evidence on diet and health to inform the Dietary Guidelines for Americans. Over time, the committee’s focus has shifted away from single nutrients or foods and toward overall dietary patterns. Nutrient and food analyses cannot account for the interactions among or the degree of independent variation of coingested nutrients and food components.¹ To advance nutrition research and inform the 2020-2025 Dietary Guidelines for Americans, understanding the role of dietary patterns in optimizing health and reducing the risk of chronic disease across the lifespan is a high priority.²

Background: As part of a healthy diet, limiting intakes of excess sodium, added sugars, saturated fat, and trans fat has been recommended. The American Heart Association recommends that children aged <2 y should avoid added sugars.

This important public health question was identified by the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) to be examined by the 2020 Dietary Guidelines Advisory Committee. The 2020 Dietary Guidelines Advisory Committee, Dietary Patterns Subcommittee conducted a systematic review to answer this question with support from the Nutrition Evidence Systematic Review (NESR) team. The goal of this systematic review was to examine the following question: What is the relationship between dietary patterns consumed and growth, size, body composition, and/or risk of overweight or obesity? Dietary patterns: Children: Limited evidence suggests that dietary patterns consumed by children or adolescents that are lower in fruits, vegetables, whole grains, and low-fat dairy while being higher in added sugars, refined grains, fried potatoes, and processed meats are associated with higher fat-mass index and BMI later in adolescence. (Grade: Limited). Dietary patterns: Adults: The 2020 Dietary Guidelines Advisory Committee reviewed newly published evidence using a systematic evidence scan and determined that the conclusion drawn by the 2015 Dietary Guidelines Advisory Committee generally reflects the current state of science. Moderate evidence indicates dietary patterns emphasizing vegetables, fruits, and whole grains; seafood and legumes; moderate in dairy products (particularly low and non-fat dairy) and alcohol; lower in meats (including red and processed meats), and low in sugar-sweetened foods and beverages, and refined grains are associated with favorable outcomes related to body weight, (including lower BMI, waist circumference, or percent body fat) or risk of obesity. Components of the dietary patterns associated with these favorable outcomes include higher intakes of unsaturated fats and lower intakes of saturated fats, cholesterol, and sodium. (2015 Dietary Guidelines Advisory Committee Grade: Moderate). Diets based on macronutrient distribution: Children: No evidence is available to determine a relationship between diets based on macronutrient distribution consumed during childhood and growth, size, body composition, and risk of overweight/obesity. (Grade: Grade not assignable). Diets Based on macronutrient distribution: Adults: Insufficient evidence is available to determine the relationship between macronutrient distributions with proportions of energy falling outside of the AMDR for at least one macronutrient and growth, size, body composition, and risk of overweight/obesity, due to methodological limitations and inconsistent results. (Grade: Grade not assignable). Two literature searches were conducted using 3 databases (PubMed, Cochrane, and Embase) to identify articles that evaluated the intervention or exposure of dietary patterns consumed and the outcomes of type 2 diabetes. A manual search was conducted to identify articles that may not have been included in the electronic databases searched. Articles were screened by two NESR analysts independently for inclusion based on pre-determined criteria. Data extraction and risk of bias assessment were conducted for each included study, and both were checked for accuracy. The Committee qualitatively synthesized the body of evidence to inform development of a conclusion statement(s), and graded the strength of evidence using pre-established criteria for risk of bias, consistency, directness, precision, and generalizability. Dietary patterns were defined as the quantities, proportions, variety, or combination of different foods, drinks, and nutrients in diets, and the frequency with which they are habitually consumed. Diets based on macronutrient distribution were considered to be those with at least one macronutrient proportion outside of the acceptable macronutrient distribution range (AMDR) for carbohydrate, fat, and/or protein, whether or not the foods/food groups consumed were provided. Studies examining energy-restricted diets that induce weight loss or treat overweight and obesity for the purposes of treating additional or other medical conditions were excluded. Eighty-eight articles were identified that met inclusion criteria and examined the relationship between dietary patterns and/or diets based on macronutrient proportion and growth, size, body composition, and/or risk of overweight or obesity. Twelve articles from prospective cohort studies were identified that examined dietary patterns consumed by children and growth, size, body composition, and/or risk of overweight or obesity, met inclusion criteria, and were published between January 2014 and October 2019. ○. Dietary patterns were assessed using a variety of methods including factor/cluster analysis, indices or scores, latent class analysis, and reduced rank regression. ○. Outcome measures varied across studies and included incidence of overweight/obesity, fat mass, lean mass, body mass index (BMI), central adiposity, and weight/height. ○. Despite variability in methods, dietary patterns in childhood or adolescence that generally reflect poorer diet quality tended to associate with higher fatmass index and BMI later in adolescence. However, the findings should be interpreted with caution due to several limitations. ○. Across the body of evidence, the direction of significant findings were mixed with relatively small and inconsistent magnitude. ○. Most of the studies assessed diet once at baseline with methods that were not necessarily valid, reliable, or applicable in children. Fifty-four articles examined dietary patterns consumed by adults and growth, size, body composition, and/or risk of overweight or obesity. The 2020 Committee determined with a systematic evidence scan that the recently published evidence was generally consistent with the body of evidence from the existing review, and a full systematic review update was not needed at this time. Therefore, the conclusion statement and grade from the existing review were carried forward. No studies identified met inclusion criteria that examined diets based on macronutrient distribution consumed by children or adolescents and growth, size, body composition, and/or risk of overweight or obesity. Thirty-one articles examined diets based on macronutrient distribution consumed by adults and growth, size, body composition, and/or risk of overweight or obesity, met inclusion criteria, and were published between January 2000 and October 2019: ○. Twenty-two articles came from randomized controlled trials (RCTs) and nine articles came from prospective cohort studies. ○. When describing and categorizing studies included in this review, the Committee did not label the diets examined as “low” or “high,” because no standard definition is currently available for, for example, “low-carbohydrate” or “high-fat” diets. Instead, the Committee focused on whether, and the extent to which, the proportions of the macronutrients were below or above the AMDR. ○. Most of the articles examined distributions in which the proportion of energy from carbohydrate was below the AMDR; fat was above the AMDR; and protein was within the AMDR in at least one of the exposure groups compared. ○. Foods or food groups consumed as part of the diet were not reported consistently. ○. Results across studies were inconsistent, with the majority of studies reporting no significant association between diets based on macronutrient distribution and growth, size, body composition, and/or risk of overweight or obesity. ○. Some studies reported diets based on macronutrient distributions with proportions of energy from carbohydrate and/or fat within or close to AMDRs compared to those that were outside AMDRs significantly associated with favorable fat-mass, BMI, waist circumference, and/or change in weight. Notably, these results were closely linked to better quality of the diet where reported, typically consisting of vegetables, fruit, whole-grains, vegetable oils, nuts, pulses, and/or lean meat or fish. ○. Numerous limitations that prevent adequate assessment across this body of evidence were identified: ■. Several studies did not directly test the difference in macronutrient proportions in the context of various dietary patterns during energy balance. ■. Although statistically significant relationships were reported, the gradient between macronutrient distributions was relatively narrow within studies (e.g., 45.3% vs. 43.8% carbohydrate) and between studies. ■. Due to the variety of methods used to estimate macronutrient intake and adjust intake for total energy, the confidence in the reported proportions of energy falling outside the AMDR is low. ■. Several studies reported to be examining one particular macronutrient of interest, such as “high-protein” or “low-carbohydrate” intake, but the proportion for that nutrient was within the AMDR.

Background: To describe the availability and nutrient composition of U.S. commercially available squeeze pouch infant and toddler foods in 2015. Materials and Methods: Data were from information presented on nutrition labels for 703 ready-to-serve, pureed food products from 24 major U.S. infant and toddler food brands. We described nutritional components (e.g., calories, fat) and compared them between packaging types (squeeze pouch versus other packaging types) within food categories. Results: 397 (56%) of the analyzed food products were packaged as squeeze pouches. Differences in 13 nutritional components between squeeze pouch versus other packaging types were generally small and varied by food category. Squeeze pouches in the fruits and vegetables, fruit-based, and vegetable-based categories were more likely to contain added sugars than other package types. Conclusion: In 2015, squeeze pouches were prevalent in the U.S. commercial infant and toddler food market. Nutrient composition differed between squeeze pouches and other packaging types for some macro- and micronutrients. Although it is recommended that infants and toddlers under two years old not consume any added sugars, a specific area of concern may be the inclusion of sources of added sugar in squeeze pouches. Linking this information with children’s dietary intake would facilitate understanding how these differences affect overall diet quality.

This important public health question was identified by the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) to be examined by the 2020 Dietary Guidelines Advisory Committee. The 2020 Dietary Guidelines Advisory Committee, Dietary Patterns Subcommittee conducted a systematic review to answer this question with support from the Nutrition Evidence Systematic Review (NESR) team. The goal of this systematic review was to examine the following question: What is the relationship between dietary patterns consumed and all-cause mortality? Dietary patterns: Strong evidence demonstrates that dietary patterns in adults and older adults characterized by vegetables, fruits, legumes, nuts, whole grains, unsaturated vegetable oils, and fish, lean meat or poultry when meat was included, are associated with decreased risk of all-cause mortality. These patterns were also relatively low in red and processed meat, high-fat dairy, and refined carbohydrates or sweets. Some of these dietary patterns also included alcoholic beverages in moderation. (Grade: Strong). Diets based on macronutrient distribution: Insufficient evidence was available to determine the relationship between diets based on macronutrient distribution and all-cause mortality. (Grade: Grade not assignable). A literature search was conducted using 3 databases (PubMed, Cochrane, Embase) to identify articles that evaluated the intervention or exposure of dietary patterns consumed and the outcome of all-cause mortality. A manual search was conducted to identify articles that may not have been included in the electronic databases searched. Articles were screened by two NESR analysts independently for inclusion based on pre-determined criteria. Data extraction and risk of bias assessment were conducted for each included study, and both were checked for accuracy. The Committee qualitatively synthesized the body of evidence to inform development of a conclusion statements, and graded the strength of evidence using pre-established criteria for risk of bias, consistency, directness, precision, and generalizability. Dietary patterns were defined as the quantities, proportions, variety, or combination of different foods, drinks, and nutrients (when available) in diets, and the frequency with which they are habitually consumed. Diets based on macronutrient distribution were examined when at least one macronutrient proportion was outside of the acceptable macronutrient distribution range (AMDR) for carbohydrate, fat, and/or protein, whether or not the foods/food groups consumed were provided. This systematic review identified 153 articles, including one randomized controlled trial and 152 prospective cohort study designs that met inclusion criteria and were published between January 2000 and October 2019. 141 studies examined the relationship between dietary patterns and all-cause mortality. The studies used multiple approaches to assess dietary patterns and all-cause mortality. ○. One RCT assigned participants to consume a “Mediterranean” dietary pattern with extra-virgin olive oil or mixed nuts compared to a control diet. ○. One-hundred ten articles examined dietary patterns using index or score analysis, ○. Twenty-five articles examined dietary patterns identified with factor and cluster analysis, ○. Eleven articles used other methods, including only reduced rank regression (RRR), comparisons based on animal-product consumption vs. avoidance, or comparisons based on ‘ultra-processed’ food consumption, to examine the relationship between dietary patterns and/or diets based on macronutrient distribution. ○. Despite the variety of different methods applied to examine or derive dietary patterns, the majority of studies finding statistically significant relationships between dietary patterns consumed and all-cause mortality risk were remarkably consistent. ○. Although the dietary patterns examined were characterized by different combinations of foods and beverages due to the variety of methods used, protective dietary patterns emerged with the following themes: ○. Patterns emphasizing higher consumption of vegetables, legumes, fruit, nuts, whole grains, fish, lean meat or poultry, and [unsaturated fats relative to saturated fats (either as a ratio of polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) relative to saturated fats/fatty acids (SFA), MUFA relative to SFA, or Olive Oil specifically] were generally associated with decreased risk of all-cause mortality. Notably, there was consistency in particular with the inclusion of fish and/or seafood. Some of these dietary patterns also included alcoholic beverages in moderation. ○. Reduced risk of all-cause mortality was observed in several studies that examined dietary patterns without animal-source foods, such as those described as vegetarian, vegan, or determined by “plant-based” diet indices. ○. Of the dietary patterns that included animal-source foods, protective associations were generally observed with relatively lower consumption of red and processed meat. However, a limitation in the evidence is methodological heterogeneity in the food categories and terminology used to classify meat. ○. The inclusion of the ratio of white vs. red meat, type and amount of dairy products, and refined carbohydrates and sweets as elements to these patterns was less consistent across the evidence. The dietary patterns that included those elements and tended to show reduced risk of all-cause mortality had, ■. higher consumption of white meat relative to red or processed meat, ■. low-fat dairy relative to high-fat dairy, and/or. ■. lower relative to higher intake of refined carbohydrates and sweets. ○. Despite the variability between approaches used to examine dietary patterns, higher adherence to dietary patterns with common labels such as “Mediterranean”, dietary-guidelines related (e.g., “Healthy Eating Index”, “DASH” scores), or “plant-based” were generally protective against all-cause mortality risk. This highlights that a high-quality dietary pattern comprised of nutrient-dense foods, regardless of the label, associated with reduced all-cause mortality risk. ○. Results based on additional analyses according to a variety of key or potential confounders generally confirmed the robustness of results. ○. Although the majority of included studies were prospective cohort studies, most adjusted for key confounders, with the exception of race and ethnicity. The results are likely generalizable to adults of various race and ethnicity though it is difficult to determine the impact that race and ethnicity specifically may have on the relationship between dietary patterns and all-cause mortality due to a lack of reporting. ○. Insufficient evidence was available to determine the relationship between dietary patterns and all-cause mortality in younger populations (~age <35 years). Twenty-eight articles examined the relationship between diets based on macronutrient distributions but results were inconsistent. ○. When describing and categorizing studies included in this review, the Committee did not label the diets examined as “low” or “high,” because no universally accepted standard definition is currently available for “low-carbohydrate” or “high-fat” diets. Instead, the Committee focused on whether, and the extent to which, the proportions of the macronutrients were below or above the AMDR. ○. Diets with proportions of carbohydrate and fat within the AMDR compared to outside the AMDRs tended to associate with reduced all-cause mortality risk, particularly when the diets examined were of higher quality (i.e., emphasizing vegetables, fruits, nuts, whole grains, legumes, fish, and/or lean meat or poultry). ○. Comparison of macronutrient distributions with or without the context of the foods/food groups comprising the dietary pattern showed inconsistent findings, likely due to several limitations that prevent the adequate assessment of the body of evidence: ○. The gradient between the macronutrient proportions compared between distributions was often small, e.g., 41% vs. 41.7%. ○. Methods used to estimate macronutrient intake differed between studies. ○. Many of the proportions outside of the AMDR were only marginally outside and often estimated differently between studies. ○. Most of these articles reported a proportion of energy from carbohydrate below and/or fat above the AMDR in at least one of the exposure groups compared. ○. Some of these articles also described the dietary pattern (i.e., foods and beverages) consumed, in addition to having macronutrient proportions outside of the AMDR.

As the science surrounding population sodium reduction evolves, monitoring and evaluating new studies on intake and health can help increase our understanding of the associated benefits and risks. Here we describe a systematic review of recent studies on sodium intake and health, examine the risk of bias (ROB) of selected studies, and provide direction for future research. Seven online databases were searched monthly from January 2015 to December 2019. We selected human studies that met specified population, intervention, comparison, outcome, time, setting/study design (PICOTS) criteria and abstracted attributes related to the study population, design, intervention, exposure, and outcomes, and evaluated ROB for the subset of studies on sodium intake and cardiovascular disease risks or indicators. Of 41,601 abstracts reviewed, 231 studies were identified that met the PICOTS criteria and ROB was assessed for 54 studies. One hundred and fifty-seven (68%) studies were observational and 161 (70%) focused on the general population. Five types of sodium interventions and a variety of urinary and dietary measurement methods were used to establish and quantify sodium intake. Five observational studies used multiple 24-h urine collections to assess sodium intake. Evidence mainly focused on cardiovascular-related indicators (48%) but encompassed an assortment of outcomes. Studies varied in ROB domains and 87% of studies evaluated were missing information on ≥1 domains. Two or more studies on each of 12 outcomes (e.g., cognition) not previously included in systematic reviews and 9 new studies at low ROB suggest the need for ongoing or updated systematic reviews of evidence on sodium intake and health. Summarizing evidence from assessments on sodium and health outcomes was limited by the various methods used to measure sodium intake and outcomes, as well as lack of details related to study design and conduct. In line with research recommendations identified by the National Academies of Science, future research is needed to identify and standardize methods for measuring sodium intake.