Eating a lot in the evening increases overall daily energy intake and is associated with a poorer quality diet in a new study exploring the calorie content and nutritional value of food relative to the time of day it is consumed.
The study, presented during this year's virtual European and International Congress on Obesity (ECOICO 2020), was led by Judith Baird, a PhD student at the Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Northern Ireland.
"If you eat most of your calorie intake earlier in the day it might help to reduce your overall calorie intake," Baird told Medscape Medical News. Our work "suggests that it might be useful to consider time of day when developing nutritional interventions [for weight loss and health] because it helps reduce overall energy intake."
Laura Johnson, PhD, is a nutritional epidemiologist at the University of Bristol, UK. She welcomed the findings for shining a light on how when we eat might affect health. "Many studies have shown that eating breakfast is typically associated with healthier diets and this research demonstrates the other end of that see-saw."
"Breakfast is notoriously the most nutrient-rich meal for most people and if you eat a greater percentage of your calories after 6 pm then it's highly likely you are missing breakfast," Johnson noted.
She added, "An outstanding and important question raised by this work is whether the time of eating per se causes the poorer diet or if it's simply a reflection of the strong cultural traditions around the type of food we eat normally at different times of day."
To investigate the association between evening eating on total daily energy intake and diet quality, Baird and colleagues drew on data from 1177 adults from the UK National Diet and Nutrition Survey, which collects detailed information on food consumption, nutrient intake, and nutritional status of the UK general population. Participants were aged 19-64 years.
Categories were devised according to the proportion of participants' daily energy intake consumed after 6 pm. The four groups were quartile1, in which eveningconsumption accounted for < 31.4% of total energy intake; quartile 2, > 31.4% to 40.4%; quartile 3, > 40.4% to 48.6%; and quartile 4, > 48.6%.
Diet quality was assessed by scoring the food diaries kept by participants using the Nutrient Rich Food Index, which classifies and ranks foods according to the ratio of important nutrients they contain relative to their energy content. Researchers did not control for energy expended during physical activity.
Results showed that the overall mean proportion of energy consumed in the evening was almost 40% of the total energy intake (39.8% 13.6%).
"Because we live in a Western society and our schedules have become more 24 hour, I expected we would consume most of our calories in the evening, but 40% was quite high," Baird remarked.
Also, those with the lowest proportion of evening energy intake (quartile 1, approximately 8437 kJ/day or approximately 2000 calories) had a significantly lower total energy intake than quartile 2 (approximately 9284 kJ/day; P < .001), quartile 3 (9108 kJ/day; P = .002), and quartile 4 (9156 kJ/day; P= .001).
In terms of diet quality, those who ate the most in the evening also consumed a nutritionally poorer diet than the other participants (P = .001 for those in quartile 4 vs quartile 1). Individuals in quartile 4 had a significantly lower Nutrient Rich Food Index score (438) than those in quartile 1 (459; P = .027), quartile 2 (465; P = .002), and quartile 3 (463; P = .005).
Baird called these findings "interesting."
The percentage of energy intake from carbohydrates and total sugars after 6 pm appeared to decrease as evening energy intake increased from quartile 1 to quartile 4, while the percentage of energy intake of fat and alcohol after 6 pm increased.
"Next, we want to look at the types of food and the eating circumstances. For example are [people]...eating in company or alone in front of the television? It might be that the setting in which people eat drives the consumption of energy-dense food...People are often more sedentary in the evening and this might affect food choice," Baird concluded.
Baird has declared no conflicts of interest. Johnson has reported institution funding from Kellogg Europe and holds research grants from the National Institutes for Health Research, Medical Research Council and World Cancer Research Fund.
ECO-ICO 2020. Presented September 1-4, 2020. Abstract 1065, LBA-056.
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