Eating dinner too late increases the risk of obesity

With the increase of the pace of life and social pressure, eating dinner later and more heartily has become a modern eating habit
.
According to statistics, 650 million adults worldwide are affected, including 42% of the adult American population, and the impact can lead to the onset of chronic diseases, including diabetes, cancer and other diseases
.

While many experts recommend a healthy diet by avoiding late-night snacks, few studies have comprehensively investigated the effects of eating too late on three main factors in weight regulation and obesity risk: regulation of calorie intake, the number of calories burned, and molecular changes
in adipose tissue.

Recently, an article
entitled "In overweight and obese adults, advanced isocaloric diets increase hunger, reduce energy expenditure, and change metabolic pathways" was published in Cell Metabolism.
Studies have found that eating timing significantly affects an individual's energy expenditure, appetite, and molecular regulatory pathways in adipose tissue
.

"We wanted to investigate the mechanisms by which eating too late promotes obesity, and previous studies have shown that eating too late is associated
with an increased risk of obesity, increased body fat, and reduced weight loss success," the researchers said.
If everything else goes on as usual, how important is dinner time? ”

The researchers tested 3 hypotheses about the mechanisms by which late food may promote positive energy balance: increased drive for energy intake (using increased hunger, decreased leptin, and increased acylated ghrelin as primary endpoints), reduced energy expenditure (using reduced calorie burn and reduced core body temperature as primary endpoints), and through coordinated molecular changes
that favor fat production.

Based on the hypothesis, the researchers conducted an indoor randomized crossover trial to simultaneously determine the effect
of dinner time on molecular regulatory mechanisms of energy intake control, energy expenditure, and adipose tissue metabolism.
Studies studied tight control of timing, amount, and type of food intake (total caloric intake and dietary composition), physical activity, posture, sleep, and light conditions
.

The researchers recruited a total of 16 overweight or obese participants
with an average age of 37 years.
For the last 2-3 weeks before the start of each experimental design, all participants maintained a regular sleep/wake cycle and consumed a calculated, timed, and pre-prepared diet
for the last 3 days before entering the laboratory.
Each participant then completed 2 protocols: the "Breakfast" protocol (dinner at 5 p.
m.
) and the "Dinner Meal" protocol (dinner at 21 o'clock)
with a 250-minute delay.

To investigate the effect of mealtime on the subjective drive for energy intake while controlling caloric intake, the researchers assessed perceived hunger and appetite
through a series of computer vision analog scales (VAS) on each test day.
It was found that the probability of hunger from eating too late increased from 10% to 20% compared to early food, almost doubled
.

The researchers next evaluated the effects of late eating on two appetite-regulating hormones: leptin, which promotes satiety, and acylated ghrelin,
which promotes hunger.
These hormones were evaluated hourly over a 24-hour period on each test day and found that eating too late reduced 24-hour leptin levels by 6% and increased the 24-hour GHRPIN-leptin ratio by 12%, while there was no significant change
in 24-hour GHRP.
During the 16-hour waking period, eating too late reduced average leptin levels by 16% and increased ghrelin by 34%.

To investigate the effects of meal timing on energy expenditure and substrate (carbohydrate and lipid) oxidation, these results were measured 12 times
over the 16-h wake-up time on each test day by indirect calorimetry.
It was found that the energy expenditure in the late feeding conditions was significantly lower than that in the early eating conditions, and the participants consumed 59.
4±13.
9 kcal less calories per day (5.
03% less)
compared to the early eating conditions.
Regarding substrate utilization, late food had no significant effect
on carbohydrate or lipid oxidation.

To investigate the effect of late feeding on the adipose tissue molecular pathway, the researchers collected subcutaneous white adipose tissue for biopsy
during early feeding and late feeding protocols.
It was found that the absolute number of differentially expressed genes in the lipid metabolism pathway was the largest, and several genes responsible for lipid decomposition were downregulated in late food, while genes responsible for lipid synthesis continued to be upregulated
.

The study proves that evening food continuously alters physiological functions and biological processes involved in regulating energy intake, consumption and storage – each of the three moving in favor of weight gain
.
These findings reveal the physiological and molecular mechanisms
underlying the correlation between eating dinner too late and an increased risk of obesity.

The researchers say the findings are not only consistent with a large number of previous studies that have also suggested that late eating may increase obesity, but also provide new clues
to this possibility.

(Source: BioValley)

China Food News(November 09, 2022 Version 03)

(Editor: Wang Jiayi).