A small new study suggests that time-restricted eating may bring benefits for blood sugar control.
- Time-restricted eating
involves eating all your meals and snacks within a window of 8-12 hours,
and consuming no calories outside that window.
- It may have benefits
including boosting metabolism, encouraging weight loss, and decreasing the
risk of some health conditions.
- Now, a small study has shown
that restricting eating to an 8-hour window at any time of day could help
people control their blood glucose levels, decreasing their risk of type 2
diabetes.
Time-restricted eating
(TRE), one of whose most popular iterations is intermittent fasting,
is becoming increasingly popular as a means of weight control.
The
most popular form involves eating only during a period of 8 to 12 hours each
day, and fasting outside that time, consuming only water and other calorie-free
drinks.
Previous
studies have suggested that TRE could have several health
benefits, which may include:
- weight loss, particularly in those with
overweight or obesity.
- improving cholesterol and triglyceride levels in
the blood, potentially decreasing the risk of cardiovascular disease
- improving cognitive function
- improving sleep quality
- anti-aging
and anti-cancer effects
- improving insulin sensitivity.
A
new study, presented at the 60th European Association for the Study of Diabetes Annual Meeting,
suggests that 8-hour TRE may help control blood glucose in people with
overweight and obesity at high risk of type 2 diabetes.
The
study, which has not yet been published in a peer-reviewed journal, was carried
out by researchers at Manchester Metropolitan and Newcastle Universities in the
United Kingdom.
Jagdish Khubchandani, PhD, professor of public health at New
Mexico State University, who was not involved in this study, told Medical News Today that:
“On the surface, the findings look interesting and in
line with other studies. One possible mechanism of action could be that TRE
could result in lesser fluctuations in blood sugar, and nutrient shortage over
some hours could increase insulin sensitivity. Some recent
reviews align with these findings.”
3 days of
time-restricted increased periods of healthy blood glucose levels
The
researchers recruited 15 people into their randomized crossover trial. The nine
women and six men had a mean body mass index (BMI) of 28, which is indicative of
overweight, a sedentary lifestyle, poor dietary habits, and a mean age 52
years, so were at high risk of developing type 2 diabetes.
The
participants alternated between 3 days of habitual eating with an eating window
of at least 14 hours per day, 3 days of early TRE where they ate only between
08.00 a.m. and 4.00 p.m., and 3 days of late TRE, where they ate between noon
and 08.00 p.m. During TRE, they fasted for 16 hours each day.
The
researchers designed eucaloric diets — matching energy intake to energy
expenditure — for the participants during the TRE phases, and they were allowed
to eat normally during the habitual eating days. These eucaloric diets were
made up of 50% carbohydrate, 30% fat and 20% protein.
All
participants wore continuous glucose monitors which assessed how much time was
spent each day with a normal blood glucose concentration — between 3.9 and 7.8
millimoles per liter (mmol/l).
The
monitors recorded three measures of blood glucose control — mean absolute
glucose, coefficient of variation, and mean
amplitude of glucose excursions.
By comparison with
habitual eating, both early and late TRE increased the time that people’s blood
glucose was within the normal range by, on average, 3.3%. It also reduced
markers of glycemic variability.
Lead
author Kelly Bowden Davies, PhD, from Manchester Metropolitan
University, said in a press release:
“Our study found that restricting eating to a window
of 8 hours per day significantly improved the daily time spent in the normal
blood glucose range and reduced fluctuations in blood glucose levels. However,
altering the 8-hour restricted eating period to earlier or later in the day did
not appear to offer additional benefits.”
While
acknowledging that these were encouraging findings, Khubchandani expressed some
concerns about the study, telling MNT that “it is unclear how such a small sample can
cover the heterogeneity among people at risk of diabetes worldwide.”
He
also questioned whether the study’s effects were actually due to TRE,
wondering: “Does TRE also at times equate to reduced consumption of calories?”
Could intermittent
fasting decrease type 2 diabetes risk?
Type
2 diabetes is strongly associated with overweight and obesity. According
to Diabetes UK, overweight and obesity account for up to 85% of
the risk of developing type 2 diabetes, and people with obesity are up to 80
times more likely to develop type 2 diabetes than those with a BMI of 22 or
under.
So,
if a person with overweight or obesity finds that TRE is an effective way to
lose weight it may help to reduce their risk of developing type 2 diabetes.
However, Khubchandani cautioned that some larger
studies have not shown the same benefits as this small study.
Bowden
Davies acknowledged that this was a preliminary study, and that further studies
were needed to determine whether TRE might be effective for some people, saying
that:
“Many people find counting calories hard to stick to
in the long term, but our study suggests that watching the clock may offer a
simple way to improve blood sugar control in people at risk of type 2 diabetes,
irrespective of when they have their 8-hour eating window, which warrants
investigation in larger studies and over the longer term.”
What are the possible
downsides of time-restricted eating?
As
well as the potential benefits shown in this study, there may be downsides to
TRE for some people.
One preliminary study of more than 20,000 adults, conducted
by the American Heart Association, found that those following an 8-hour TRE
schedule had a 91% higher risk of death from cardiovascular disease, and no
increase in longevity, compared with those following a standard 12-16 hour
eating schedule.
The
authors of this study suggest that TRE may have short-term benefits, but could
have adverse effects over the long term.
And,
while it might help decrease a person’s risk of developing type 2 diabetes, TRE
is not generally advisable for those with type 1, or
insulin-dependent, diabetes.
If
they have obesity and need to lose weight, it may be recommended under
the close supervision of a health professional to ensure that
their blood glucose levels are constantly monitored.
People
who are older, pregnant, breastfeeding, trying to conceive, have low blood
pressure, or are taking medications for blood pressure or heart disease, should
also consult a healthcare professional before they consider intermittent
fasting.
“Given the uncertainty, individuals at risk of
diabetes should consult a qualified doctor. For the general public, get blood
sugar checked regularly. One size doesn’t fit all and diabetes prevention
should be more personalized.”– Jagdish Khubchandani, PhD
No comments:
Post a Comment