About 42% of adult Americans in the United States are obese, which increases the risk of developing chronic diseases like diabetes, cancer, and other illnesses.
Though several healthy diet adages discourage late-night munching, few studies have thoroughly examined the combined impacts of late eating on the three key regulators of body weight.
Few research have thoroughly explored how late eating affects all three factors that regulate body weight and raise the risk of obesity at the same time:
● Regulation of calorie intake,
● The number of calories you burn, and
● Molecular changes in fat tissue.
Although several healthy eating adages prohibit late-night munching, few research have examined the simultaneous effects of late eating on all three players.
According to experimental data from a recent study, eating late results in decreased energy expenditure, increased appetite, and alterations in adipose tissue, all of which may raise the risk of obesity.
“We and others have already conducted research that have shown eating in the evening increases the chance of becoming obese, increases body fat, and thwarts weight loss efforts. We were curious as to why.”
First author Nina Vujovic, PhD, works in the Brigham’s Division of Sleep and Circadian Disorders and is a researcher in the Medical Chronobiology Program.
“When everything else is constant, does the time we eat matter?”
And we discovered that eating four hours later significantly affects our levels of hunger, how we burn calories after eating, and how we retain fat.
Each participant did two lab protocols:
One had a strict early mealtime routine, while the other had the identical meals at the exact same time but four hours later in the day.
In the final two to three weeks before starting each in-lab regimen, participants maintained regular sleep and wake times, and in the final three days before entering the lab, they strictly followed regular meals and mealtimes at home.
During laboratory testing in both the early and late eating protocols, researchers took biopsies of adipose tissue from a subset of participants to enable comparison of gene expression patterns/levels between these two eating conditions.
The findings showed that eating later had significant impacts on the hunger and appetite-controlling chemicals leptin and ghrelin, which affect our desire to eat. Leptin levels, which indicate fullness, were specifically lower over the course of 24 hours in the late meal condition compared to the early feeding conditions.
Participants who ate later burnt calories more slowly and showed altered gene expression in their adipose tissue, which promotes greater adipogenesis and decreased lipolysis.
These results reveal convergent physiological and molecular mechanisms that underlie the association between eating later in the day and a higher risk of obesity.
Researchers were able to identify changes in the various control systems involved in energy balance, a sign of how our bodies use the food we eat, by using a randomised crossover study and strictly controlling for behavioural and environmental factors like physical activity, posture, sleep, and light exposure.
In this study, we isolated these effects by adjusting for confounding factors including calorie intake, exercise, sleep, and light exposure; but, in real life, many of these aspects may also be influenced by meal timing, sleep quality, and other factors.
We must at least take into account how other behavioural and environmental factors affect these biochemical processes underlying obesity risk in larger-scale research when strict control of all these factors is not practical.