FIFTEEN-YEAR TRENDS IN THE PATTERNS OF MEAL TIMING AND EATING FREQUENCY AMONG US ADULTS

Understanding patterns of eating behavior may provide insights into contributors to obesity and metabolic diseases. To characterize trends in meal timing and frequency in US population age >19 years, we performed a serial cross-sectional analysis of 8 National Health and Nutrition Examination Survey (NHANES) cycles (2003-2018) on 34,470 adults (52.5% women and 21% black). Time of food and beverage intake was extracted from two 24-hour food recalls. The following meal timing measures were defined: 1) The time of the last and first calorie intake either from food or drink, 2) Eating window: The time elapsed between the first and last food intake, 3) Calorie midpoint time: The time when half of the calories for the day were consumed, 4) Late night eating: Consumption of ≥33% of total daily energy between 5:00pm and midnight, and 5) Eating frequency: Frequency of food or beverage consumption >0 kcal which were >15 minutes apart. From 2003 to 2018, survey-weighted mean (±SE) of eating window decreased from 12.21±0.06 to 12.02±0.05 hours/d (Ptrend=0.002). Time of the last calorie intake significantly decreased from 20.31±0.04 to 20.09±0.03 hours/d, while the time of first calorie intake and eating frequency remained unchanged. More than two-third of participants consumed ≥33% of total daily energy after 5:00pm. Over the 15-year span, composition of diet has also changed, including a decline in total calorie intake and percentage of energy from carbohydrate intake, while percentage of energy from dietary fats increased, Ptrend< 0.05. Patterns of eating behavior have changed in American adults over time.