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.

Structured lifestyle interventions through cardiac rehabilitation (CR) are critical to improving the outcome of patients with cardiovascular disease (CVD) and cardiometabolic risk factors. CR programs\' variability in real-world practice may impact CR effects. This study evaluates intensive CR (ICR) and standard CR (SCR) programs for improving cardiometabolic, psychosocial, and clinical outcomes in high-risk CVD patients undergoing guideline-based therapies. Both programs provided lifestyle counseling and the same supervised exercise component. ICR additionally included a specialized plant-based diet, stress management, and social support. Changes in body weight (BW), low-density lipoprotein cholesterol (LDL-C), and exercise capacity (EC) were primary outcomes. A total of 314 patients (101 ICR and 213 SCR, aged 66 ± 13 years, 75% overweight/obese, 90% coronary artery disease, 29% heart failure, 54% non-optimal LDL-C, 43% depressive symptoms) were included. Adherence to ICR was 96% vs. 68% for SCR. Only ICR resulted in a decrease in BW (3.4%), LDL-C (11.3%), other atherogenic lipids, glycated hemoglobin, and systolic blood pressure. Both ICR and SCR increased EC (52.2% and 48.7%, respectively) and improved adiposity indices, diastolic blood pressure, cholesterol intake, depression, and quality of life, but more for ICR. Within 12.6 ± 4.8 months post-CR, major adverse cardiac events were less likely in the ICR than SCR group (11% vs. 17%), especially heart failure hospitalizations (2% vs. 8%). A comprehensive ICR enhanced by a plant-based diet and psychosocial management is feasible and effective for improving the outcomes in high-risk CVD patients in real-world practice.