Abordagem crononutricional do consumo alimentar e sua associação com a ingestão dietética e obesidade em adultos americanos: Dados do National Health and Nutrition Examination Survey (NHANES) 2017-2018

Abstract

Introduction: Obesity poses a global health challenge, recognized as a chronic, recurring, and multifactorial condition associated with various health risks. Comprehensive obesity treatment considers multiple approaches, and chrononutrition, an emerging field that links the circadian system with meal timing and energy distribution throughout the day, emerges as a relevant variable. It has shown a significant relationship with Body Mass Index (BMI), suggesting that not only "what" or "how much" we eat matters but also emphasizes the potential effects of "when" we eat on bodily mechanisms and health. However, epidemiological studies exploring chrononutrition parameters, dietary intake, and BMI are scarce, highlighting the need for further investigations in this field. Objective: To investigate the association of chrononutrition variables with dietary intake and body weight at the population level. An additional aim of article 1 was to investigate these associations according to chronotype. Methods: Two cross-sectional studies (Article 1: n = 1,184; Article 2: n = 2,937) were conducted with individuals aged over 18 years, participants in the National Health and Nutrition Examination Survey (NHANES) 2017-2018. Data on meal timing and dietary intake were collected through two 24-hour dietary recalls. Caloric midpoint (defined as the time of day when 50% of total calories are consumed), eating durantin (interval between the first and last meal), eating midpoint variability (defined as the absolute difference between the midpoint of the first and last mealtimes on weekends and weekdays), sleep end-first meal interval, and last meal-sleep onset interval were determined by mealtime. Chronotype was assessed by participants' mid-sleep time on weekends, adjusted for sleep debt. Linear regression analyses were conducted to investigate associations between variables in both articles. In the first article, the sample was categorized into chronotype tertiles for further analysis, while in the second article, the sample was stratified according to BMI cutoffs (BMI < 25 kg/m²; BMI ≥ 25 < 30 kg/m²; BMI ≥ 30 kg/m²). Results: The first study found associations indicating a positive relationship between eating midpoint variability and BMI (β = 1.2; 95%CI 1.13 – 1.27) among individuals with an evening chronotype. Those with a morning chronotype showed a positive association between eating midpoint variability and calorie (β = 96.9; 95%CI 92.9 – 101.7), carbohydrate (β = 11.96; 95%CI11.2 – 12.6), fat (β = 3.69; 95%CI 3.4 – 3.8), cholesterol (β = 32.75; 95%CI 30.9 – 34.6), and sugar (β = 8.84; 95%CI 8.3 – 9.3) intake on weekends. The findings of the second article indicate a trend of increased total energy consumption (kcal) (p <0.001; p<0.001; p<0.001; p<0.001), carbohydrates (g); protein (g), fat (g), and sugar (g) as the sleep end-first meal interval decreases and the last meal-sleep onset interval, eating duration, and energy intake after 8 pm increases (p<0.005). Additionally, the findings suggest a trend of increased BMI in the group with BMI ≥ 30 kg/m² (p = 0.018) as the sleep end-first meal interval increases and in the group with BMI < 25 kg/m² (p = 0.006) as eating duration increases. Conclusion: The variation in meal timings during weekdays and weekends, along with the habit of eating later, may be associated with increased food consumption and less effective weight management. These findings underscore the importance of chrononutrition in dietary and weight management, indicating the need for comprehensive epidemiological research and randomized clinical trials to understand the underlying mechanisms of these correlations, and, also to provide a solid foundation for future updates in nutritional guidelines.