BACKGROUND: Mischaracterization of dietary intake by patients and study participants is a common problem that presents challenges to clinical and public health approaches to improve diet quality, identify healthy eating patterns, and reduce the risk of chronic disease.
OBJECTIVE: This study examined participants\' self-reported adherence to low-carbohydrate and low-fat diets compared with their estimated adherence using up to 2 24-hour recalls.
METHODS: This cross-sectional study acquired data on dietary intake from respondents in the National Health and Nutrition Examination Survey, 2007-2018.
METHODS: This study included 30 219 respondents aged 20 years and older who had complete and reliable dietary data and were not pregnant or breastfeeding.
METHODS: The main outcome was prevalence of self-reported and estimated adherence to low-carbohydrate or low-fat diet patterns.
METHODS: Self-reported adherence to low-carbohydrate or low-fat diets was evaluated using responses to questionnaires. Estimated adherence to these diets was assessed using data from up to 2 24-hour recalls and usual intake methodology developed by the National Cancer Institute.
RESULTS: Of the 1.4% of participants who reported following a low-carbohydrate diet, estimated adherence (<26% energy from carbohydrates) using 24-hour recalls was 4.1%, whereas estimated adherence among those that did not report following a low-carbohydrate diet was <1% (P value for difference = .014). Of the 2.0% of participants who reported following a low-fat diet, estimated adherence (<30% energy from fat) was 23.0%, whereas estimated adherence among those who did not report following a low-fat diet was 17.8% (P value for difference = .048).
CONCLUSIONS: This research demonstrates that most individuals mischaracterized their diet pattern when compared with up to 2 24-hour recalls. These findings emphasize the need for clinicians and public health professionals to be cautious when interpreting individuals\' self-reported diet patterns, and should aim to collect more detailed dietary data when possible.

UNASSIGNED: Fifty-two percent of adults in the United States reported following a popular diet pattern in 2022, yet there is limited information on daily micronutrient intakes associated with these diet patterns. The objective of the present study was to model the impact on micronutrient intake when foods highest in added sugar and sodium were replaced with healthier alternatives to align with the Dietary Guidelines for Americans recommendations.
UNASSIGNED: Dietary data were acquired from 34,411 adults ≥ 20 y in the National Health and Nutrition Examination Survey, 2005-2018. The National Cancer Institute methodology was used to estimate usual dietary intake at baseline of 17 micronutrients using information from up to two dietary recalls per person. A food substitution model was used to evaluate the impact on micronutrient intake when three servings of foods highest in added sugar and sodium were substituted with healthier alternatives.
UNASSIGNED: Dietary modeling to replace foods highest in added sugar with healthier alternatives increased the mean intake of fat-soluble vitamins (0.15% for vitamin A to 4.28% for vitamin K), most water-soluble vitamins (0.01% for vitamin B1 to 12.09% for vitamin C), and most minerals (0.01% for sodium to 4.44% for potassium) across all diet patterns. Replacing foods highest in sodium had mixed effects on the mean intake of micronutrients. The intake of most fatsoluble vitamins increased by 1.37-6.53% (particularly vitamin A and D), yet while the intake of some water-soluble vitamins and minerals increased by 0.18-2.64% (particularly vitamin B2, calcium, and iron) others decreased by 0.56-10.38% (notably vitamin B3 and B6, magnesium, sodium, and potassium).
UNASSIGNED: Modeled replacement of foods highest in added sugar led to more favorable changes in mean micronutrient intake compared to modeled replacement of foods highest in sodium. Due to the composite nature of mixed dishes that include multiple ingredients, food substitutions may result in both favorable and unfavorable changes in micronutrient intake. These findings highlight the challenges of making singleitem food substitutions to increase micronutrient intake and call for further research to evaluate optimal combinations of replacement foods to maximize the intake of all micronutrients simultaneously.

UNASSIGNED: Few studies have evaluated the sustainability of popular diet patterns in the US, which limits policy action and impedes consumer efficacy to make sustainable dietary changes. This study filled this gap by evaluating the relationship between diet quality, greenhouse gas emissions (GHGE), and diet cost for plant-based, restricted carbohydrate, low grain, low fat, and time restricted diet patterns.
UNASSIGNED: Dietary data were retrieved from the National Health and Nutrition Examination Survey (2011-2018, n = 8,146) and linked with data on GHGE and food prices from publicly available databases. Diet quality was measured using the Healthy Eating Index-2015. The present study (1) compared the mean diet quality, GHGE, and diet cost between diet patterns, (2) evaluated the association of diet quality to GHGE and diet cost for each diet pattern, and (3) estimated the contribution of food sources to GHGE and diet cost for each diet pattern.
UNASSIGNED: Higher diet quality was associated with lower GHGE for the general population and for most diet patterns (p < 0.01) except for the plant-based and time restricted diet patterns (p > 0.05). Higher diet quality was associated with higher cost for the general population and for all dietary patterns (p < 0.01) except the time restricted diet pattern (p > 0.05). Protein foods, mostly beef, accounted for the largest share of GHGE (29-40%) and diet cost (28-47%) for all diet patterns except plant-based.
UNASSIGNED: Higher diet quality was associated with lower GHGE but was often accompanied by higher diet cost. These sustainability trade-offs can help inform major policy discussions in the US and shed light on further research needs in the area of food systems transformation.

UNASSIGNED: Cardiometabolic diseases (CMDs), which include heart disease, stroke, and diabetes, account for over one-third of the mortality burden in the United States annually. Nearly one-half of all deaths from CMD are attributable to suboptimal diet quality, and many Americans are turning to special diets for general health improvement. Among the most popular of these diets restrict daily carbohydrate intake to <45% of energy, yet their association with CMD is not well understood.
UNASSIGNED: This study evaluated the association between restricted carbohydrate diets and prevalent CMD, stratified by fat intake.
UNASSIGNED: Dietary and CMD data were retrieved from 19,078 participants aged ≥20 y in the National Health and Nutrition Examination Survey, 1999-2018. The National Cancer Institute methodology was used to assess usual dietary intake.
UNASSIGNED: Compared to participants that met recommendations for all macronutrients, those that consumed restricted carbohydrate diets were 1.15 (95% CI: 1.14, 1.16) times as likely to have CMD; and those that met recommendations for carbohydrates, but not all macronutrients, were 1.02 (95% CI: 1.02, 1.03) times as likely to have CMD. Higher intakes of saturated and polyunsaturated fat were associated with greater prevalence of CMD in restricted and recommended carbohydrate intake groups. Higher intake of monounsaturated fat was associated with lower prevalence of CMD among participants that met carbohydrate, but not all macronutrient, recommendations.
UNASSIGNED: To our knowledge, this is the first nationally representative study to evaluate the relationship between carbohydrate restriction and CMD, stratifying by fat intake. Greater efforts are needed to understand longitudinal relationships between carbohydrate restriction and CMD.

Adults in the United States are increasingly following \'popular\' diet patterns that restrict food groups, macronutrients, or eating time. However, the intake of food groups associated with these diet patterns has not been well characterized. The objectives of this study were to (1) characterize the mean intake of food groups among consumers of popular diet patterns in the US, and (2) model the effect of targeted food substitutions on the intake of food groups. Data were acquired from the National Health and Nutrition Examination Survey, 2005-2018 (n = 34,411). A diet model was developed to assess the effects of replacing one serving each of foods highest in added sugar, sodium, saturated fat, and refined grains with healthy alternatives on the intake of key food groups for each diet pattern. Modeled replacement resulted in increased intake of fruit and whole grains and decreased intake of dairy for most diet patterns, while the effects on the intake of vegetables, protein foods, and oils were variable across diet patterns. The complexity of the natural eating environment, in which many people consume mixed dishes that include both healthy and less healthy ingredients, produces a challenge for health professionals when providing dietary counseling. Nevertheless, this substitution approach may help improve adherence to dietary guidelines, especially if used as a steppingstone for further dietary improvement.

UNASSIGNED: Many Americans have adopted popular diet patterns for general health improvement that restrict specific foods, macronutrients, or eating time. However, there is limited evidence to characterize the quality of these diet patterns.
UNASSIGNED: This study 1) evaluated the quality of popular diet patterns in the United States and 2) modeled the effect of targeted food substitutions on diet quality.
UNASSIGNED: Dietary data from 34,411 adults ≥20 y old were acquired from the NHANES, 2005-2018. Dietary intake was assessed using the National Cancer Institute\'s usual intake methodology, and the Healthy Eating Index-2015 was used to evaluate diet quality. A diet model was used to evaluate the effect of targeted food substitutions on diet quality.
UNASSIGNED: A pescatarian diet pattern had the highest diet quality (65.2; 95% CI: 64.0, 66.4), followed by vegetarian (63.0; 95% CI: 62.0, 64.0), low-grain (62.0; 95% CI: 61.6, 62.4), restricted-carbohydrate (56.9; 95% CI: 56.6, 57.3), time-restricted (55.2; 95% CI: 54.8, 55.5), and high-protein (51.8; 95% CI: 51.0, 62.7) diet patterns. Modeled replacement of ≤3 daily servings of foods highest in added sugar, sodium, saturated fat, and refined grains with alternative foods led to an increase in diet quality and a decrease in energy intake for most diet patterns.
UNASSIGNED: Low diet quality was observed for all popular diet patterns evaluated in this study. Modeled dietary shifts that align with recommendations to choose foods lower in added sugar, sodium, saturated fat, and refined grains led to modest improvements in diet quality and larger reductions of energy intake. Greater efforts are needed to encourage the adoption of dietary patterns that emphasize consumption of a variety of high-quality food groups.

Gluten-free (GF) foods are typically less nutritious and more expensive than their gluten-containing variants, yet people without a diagnosed gluten sensitivity continue to adopt this diet. There is a lack of research about what factors drive people without Celiac disease or non-Celiac gluten sensitivity to follow the GF diet.
A nationally representative sample of 2982 US residents without a diagnosed gluten sensitivity were surveyed about their attitudes, perceptions, and experiences with the GF diet. Logistic regression was used to compare respondents who were currently avoiding or had avoided gluten previously (GF consumer) to respondents who had never tried a GF diet (non-GF consumer).
Over one-fifth of respondents were GF consumers. Beliefs that a gluten-reduced diet is healthier (OR 1.69; 95% CI [1.30,2.18]), that GF products are more nutritious (OR 1.46, 95% CI [1.11,1.90), and that a GF diet can help clear acne (OR 1.46; 95% CI [1.13,1.88]) were all positively associated with trying a GF diet. Personal research was the most influential source of information associated with trying a GF diet (OR 2.92; 95% CI [1.91,4.52]). This was followed by \"healthcare center or health professional\" (OR 2.57; 95% CI [1.71,3.90]. Respondents who were never encouraged to try the GF diet were less likely to try the diet (OR 0.33, 95% CI [0.23,0.46]).
Positive, but scientifically unsubstantiated, beliefs about the benefits of the GF diet were strongly associated with trying a GF diet, and the source of recommendation to try a GF diet was important.

To describe characteristics of self-identified popular diet followers and compare mean BMI across these diets, stratified by time following diet.
Cross-sectional, web-based survey administered in 2015.
Non-localised, international survey.
Self-selected followers of popular diets (n 9019) were recruited to the survey via social media and email announcements by diet community leaders, categorised into eight major diet groups.
General linear models were used to compare mean BMI among (1) short-term (<1 year) and long-term (≥1 year) followers within diet groups and (2) those identifying as \'try to eat healthy\' (TTEH) to all other diet groups, stratified by time following the specific diet. Participants were 82 % female, 93 % White and 96 % non-Hispanic. Geometric mean BMI was lower (P < 0·05 for all) among longer-term followers (≥1 year) of whole food, plant-based (WFPB), vegan, whole food and low-carb diets compared with shorter-term followers. Among those following their diet for 1-5 years (n 4067), geometric mean BMI (kg/m2) were lower (P < 0·05 for all) for all groups compared with TTEH (26·4 kg/m2): WFPB (23·2 kg/m2), vegan (23·5 kg/m2), Paleo (24·6 kg/m2), vegetarian (25·0 kg/m2), whole food (24·6 kg/m2), Weston A. Price (23·5 kg/m2) and low-carb (24·7 kg/m2).
Our findings suggest that BMI is lower among individuals who made active decisions to adhere to a specific diet, particularly more plant-based diets and/or diets limiting highly processed foods, compared with those who simply TTEH. BMI is also lower among individuals who follow intentional eating plans for longer time periods.