Does eating at specific times make you lose extra weight? A recent study answers you

Over the past years, intermittent fasting IF has become one of the most popular diets, due to its promise of weight control.

Dr. Mark Hyman, director of the Cleveland Clinic Center for Functional Medicine and author of bestselling cookbooks, defines intermittent fasting as "eating nothing" with one of three regimens;

The first is the time-restricted diet, 8-16, which means eating within 8 hours of the day, then fasting for about 16 hours, before eating again, which is the most common type of intermittent fasting.

The second is to fast one day alternately with another, in which 500 calories are consumed in one meal.

And finally the third, the 5-2 diet, which includes 5 eating days, then eating only about 25% of the required calories for the remaining two days of the week.

But the interesting thing is that a review - conducted in 2019 - on 9 out of 11 studies, "did not show any differences between these three regimens, in terms of weight loss or body fat loss", in conjunction with a study published in the same period, She noted that "intermittent fasting is no better than a regular diet."

And the American newspaper “The New York Times” published the results of a recent Chinese study that refuted the fact that the “time-restricted eating” system is an essential pillar of the intermittent fasting diet, saying that it “does not provide any benefit.”

May be dangerous for people who have diabetes or take blood pressure medications (Shutterstock)

There are no significant differences

Time-restricted eating is an attractive weight-loss idea that involves eating less for 6 to 8 hours each day, according to a set schedule.

Studies in mice, or small studies in obese people (some studies involving 11 people, lasting 4 days), indicated that this method "may help lose pounds".

Until this "strict" study - as described by the writer Gina Kolata - conducted by researchers at the Chinese "Southern Medical University", and over a year, 139 obese people of both sexes participated;

One group of them was asked to limit their daily food intake to 1500-1800 calories per day for men, and 1200-1500 calories per day for women.

Men and women in the placebo group were told to consume the same amount of calories, but only on the condition that they "eat only between 8 a.m. and 4 p.m.".

To ensure accurate adherence, study participants were asked to keep food records and photograph all the foods they ate.

At the end of the year, the researchers found no significant differences between the two groups, either in people who ate the same calorie-restricted diet between 8 a.m. and 4 p.m. at any time during the day.

The average weight loss in both cases was 14 to 18 pounds (6.35 to 8.20 kilograms);

There were no significant statistical differences in the measurements of waist circumference, body fat and body mass, and the scientists did not find any differences in risk factors, such as blood glucose levels, insulin sensitivity, blood lipids, or blood pressure.

Time-restricted eating can cause headaches, lethargy, lack of focus and constipation (Getty Images)

There is no point in eating a time-restricted diet

Colata tells us that this new study wasn't the first to refute the time-restricted eating diet, but that previous studies were often of smaller scale, or shorter duration.

Dr. Ethan Weiss, a diet researcher at the University of California, led a team of researchers who conducted a study - published in late 2020 - in which some of the 116 participants were asked to eat 3 meals a day, with snacks if they felt hungry, while the rest were asked. Eat whatever they want, but at a restricted time between noon and 8 pm.

The study showed that participants lost a small amount of weight, averaging 2 pounds (900 grams) in the time-restricted eating group and 1.5 pounds (680 grams) in the other group, a difference that was not statistically significant.

Weiss told the New York Times that he couldn't believe the results, and asked his team to re-analyze the data 4 times, "until they told him that more iterations didn't change the results";

"The results of the new study reinforced his conviction that time-restricted eating does not provide any benefit," he added.

What this 12-week study found was confirmed by this year-long study, "without finding a benefit in eating time-restricted food."

This was preceded by expert Rachel Clarkson - when she told the BBC earlier this year - "intermittent fasting may not be the right way for people seeking to lose weight."

Courtney Peterson, a researcher in time-restricted eating, backed it up, telling the New York Times, "We don't have a clear answer yet as to whether this strategy helps people lose weight."

Risks to watch out for

In 2020, Harvard Health conducted a preliminary evaluation of the side effects of the intermittent fasting diet, and recommended that you discuss them with your doctor before embarking on it;

Headaches, lethargy, lack of focus and constipation, as well as overeating, can be under pressure from appetite hormones and the hunger center in the brain, which become overly active when we are deprived of food.

It may also cause elderly people to lose a lot of weight, affecting bones, energy and the immune system, and may be dangerous for people who have diabetes or take blood pressure medications.