A paper in Science explains why eating late at night can lead to weight gain and diabetes

Scientists at Northwestern Medical College have discovered the
mechanism by which late-night eating is associated with weight gain and diabetes.
The links between eating time, sleep and obesity are well known, but little
is known.
Studies have shown that overnutrition disrupts circadian rhythms and alters adipose tissue
.

New research from Northwestern University suggests for the first time that energy release may be the molecular mechanism
by which our internal clock controls energy balance.
Based on this understanding, scientists have also found that in the light environment of the Earth's rotation, daytime is the ideal time, when energy is dissipated in the form of heat
.
The findings have implications for a wide range of implications, from dieting to sleep deprivation and the way
we feed patients who need long-term nutritional help.

The paper, titled "Time-limited feeding alleviates obesity through adipocyte thermogenesis," was published
in the journal Science.

Dr.
Joseph Bass, professor and author of Northwestern University's Feinberg School of Medicine, said: "It is well known that although little is known about this, the destruction of the biological clock is the destruction of metabolism
.
" He is also an endocrinologist at
Northwestern Medicine.

Bass said: "When animals eat Western-style buffets — high-fat, high-carbohydrate — the biological clock is disrupted
.
The biological clock is sensitive to when people eat, especially in adipose tissue, and this sensitivity can be disrupted
by a high-fat diet.
We still don't understand why, but what we do know is that when animals become obese, they start eating more
when they should be sleeping.
This study shows why this is important
.
”

Chelsea Hepler, a postdoc in Bass' lab, was the first author of the study and did many biochemical and genetic experiments
for the team's hypothesis.
Now Duke's Rana Gupta is also a key collaborator
.

Disrupt the internal clock

In this study, nocturnal rodents were fed high-fat foods either during the inactive (light) or active (dark) periods
.
During the week, the mice that ate during light hours gained more
weight than those that ate during dark hours.
The team also set the temperature to 30 degrees, at which the rats consume the least amount of energy, to mitigate the effect
of temperature on the findings.

"We think it could be a component of energy balance, where rats expend more energy at a given time," Hepler said
.
"That's why they can eat the same amount of food at different times of the day, and it's healthier
to eat during active times than when they should be sleeping.
"

As energy expenditure increased, the team began studying the metabolism of adipose tissue to determine whether the same effect
would occur in endocrine organs.
They found that it did, and that mice with genetically enhanced thermogenesis (or release heat through fat cells) could prevent weight gain and improve health
.

Hepler also discovered the useless creatine cycle, where creatine (a molecule that helps maintain energy) undergoes the storage and release of chemical energy in adipose tissue, meaning creatine may be a potential mechanism
for heat release.

Intermittent fasting and gastric feeding tubes

More than 20 years ago, Bass and his colleagues at Northwestern University conducted a study that found a relationship
between molecular clocks and weight, obesity and metabolism in animals.
Bass's lab focuses on studying physiology with a genetic approach, and the challenge is to figure out what it all means and find the control mechanisms
that produce this relationship.
This study takes them one step further
.
Bass said the findings could inform chronic care, especially those with
gastric feeding tubes.
Patients usually eat at night when they go to bed because this is when they release the least
amount of energy.
These patients tend to have high rates of diabetes and obesity, which Bass believes explains why
.
He also wants to know how the study will affect the treatment
of type 2 diabetes.
For example, should meal times be taken into account when injecting insulin?

Hepler will continue to study creatine metabolism
.
"We need to figure out how the circadian clock controls creatine metabolism so we can figure out how to boost creatine metabolism
," she said.
The clock has a large impact on metabolic health at the adipose tissue level, but we don't yet know how big the effect is
.
”

Chelsea Hepler, Benjamin J.
Weidemann, Nathan J.
Waldeck, Biliana Marcheva, Jonathan Cedernaes, Anneke K.
Thorne, Yumiko Kobayashi, Rino Nozawa, Marsha V.
Newman, Peng Gao, Mengle Shao, Kathryn M.
Ramsey, Rana K.
Gupta, Joseph Bass.
Time-restricted feeding mitigates obesity through adipocyte thermogenesis.
Science, 2022; 378 (6617): 276