[ad_1]
In the ever-evolving quest to live longer and healthier, we know that diet plays a fundamental role. In recent years, scientists have also focused on the potential of intermittent fasting, a diet that relies on when you eat, no what you eat.
However, new research suggests that you may not be able to achieve what some intermittent fasts seek when they adopt it as their eating pattern.
Growing evidence, primarily in animals and relatively small groups of people, suggests that intermittent fasting (sometimes called time-restricted feeding) can improve metabolic function, prevent certain diseases, and even extend lifespan. Based on these findings, intermittent fasting (alternating periods of normal eating and fasting) has exploded in popularity. In 2019, it was the most Googled diet on the planet.
Intermittent fasting is also advertised as a simple weight loss strategy: no calorie counting, no complicated recipes, or eliminating certain involved food groups.
However, in a recent randomized clinical trial, one of the most rigorous eating pattern studies to date, researchers tracked 116 obese and overweight people for three months to see if the scientific evidence lives up to the standards. expectations.
The team, in turn, found that time-restricted meals or intermittent fasting did not help people lose weight significantly more than simply eating three meals a day. Instead, it had an unwanted side effect: loss of muscle mass.
Can Intermittent Fasting Really Help You Lose Weight?
Ethan Weiss is a co-author of the study and a cardiologist at the University of California, San Francisco. His team published their findings published Monday in the journal. JAMA Internal Medicine.
Prior to this work, Weiss practiced time-restricted eating in the past. seven years. After analyzing these results, he stopped.
“No matter how you look at it, time-restricted eating resulted in very modest weight loss [about .2 pounds per week over 12 weeks on average]”Says Weiss Reverse. “It didn’t offer any other metabolic benefits. And then there was the worrying sign of lean mass loss.”
Victoria Catenacci, endocrinologist and metabolism expert at the University of Colorado, Anschutz Health and Wellness Center, says the study was “well-run,” but says factors such as window timing, lack of behavioral support and decreased physical activity in the fasting group may have affected the results. Catenacci was not involved in the study.
“This well-designed study shows that eating only late with time restriction without behavioral support does not result in clinically significant weight loss for 12 weeks,” says Catenacci. Reverse. She notes that this study is another reminder of the critical need to “rigorously evaluate weight-loss interventions, such as time-restricted eating, before recommending them to the general public.”
Catenacci also acknowledges that there are still many open questions in regards to this way of eating, arguing that the study does not “close the door to time-restricted eating as a weight-loss intervention” or as an intervention that may provoke other positive effects. , including longevity.
What the study examined: To determine how intermittent fasting or time-restricted eating influences weight and metabolism, Weiss and her team recruited a group of 116 people who were classified as obese or overweight.
The researchers divided the group into two dietary patterns. Half practiced a time-restricted daily diet: they ate all their meals between noon and 8:00 pm and then fasted for 16 hours. Only non-calorie drinks were allowed outside the window to eat.
The other half ate three meals a day, including snacks. Neither group received instructions on what or how much to eat during the day. They were also not instructed to exercise or refrain from exercising.
For three months, the researchers tracked the group’s weight and metabolic results using a mobile app, surveys, and a Bluetooth scale. Each participant weighed himself daily in the morning before eating or drinking.
Results and explanation – The study researchers predicted that the fasting group would lose more weight than the three-meal-a-day group. But for 12 weeks, there was no greater weight loss with a restricted diet compared to the constant food group.
There were also no significant differences in fat mass, fasting insulin, blood sugar, HbA1C, or blood lipids between the two groups.
“… There is nothing magical on a time-restricted late feeding window for short-term weight loss. “
“The minimal weight loss suggests they did not achieve a significant energy deficit,” says Catenacci. “I think this suggests that there is nothing magical about a time-restricted late feeding window for short-term weight loss.”
During the course of the study, participants in the fasting group lost about three and a half pounds. But most of the pounds lost was not fat.
Fundamentally, it was lean mass, including muscle. Typically, about 20 to 30 percent of total weight loss is lean mass. In this study, the lean mass loss ratio was 65 percent.
“You don’t want to lose lean mass. You want to lose fat mass,” says Weiss. “Here we find that two-thirds of the weight loss comes from lean mass.”
There are a number of potential factors that lead fasting participants to lose lean mass, one of which is that participants may not be eating enough protein or not getting enough physical activity. On average, the fasting participants walked about 2,500 fewer steps per day, a change in activity that could help keep their weights unchanged and their lean mass decrease.
It is also possible that fasting later in the day does not curb energy intake which would result in weight loss.
“Preclinical data suggest that an early restricted feeding window may have greater metabolic benefits and, in practical terms, a [eating] The window is more likely to result in higher calorie restriction since most people currently consume most of their calories later in the day and at night, “Catenacci explains.
She recommends that, in the future, rigorous trials should evaluate other nuances of intermittent fasting, such as eating earlier in the day or combining it with a low-calorie diet.
What’s Next for Intermittent Fasting? After publication, the study by Weiss and his team sparked immediate discussion, with experts evaluating the results on social media. Some argue that study participants were not quick enough or early in the day to see real benefit. Others say that to see the results of weight loss, the eating pattern must be combined with other diets.
Ultimately, the essay shows what many studies on nutrition and exercise do: that there is no one-size-fits-all solution or magic strategy for losing weight and living a long, healthy life.
“This is just a regimen, but it highlights how easy it is to think something works when it doesn’t,” says Weiss. “Or perhaps more accurately, that anything works.”
The findings certainly don’t support that there is any major effect of fasting, Weiss adds.
“Longevity? Who the hell knows,” says Weiss. “Weight and metabolic end points are tough enough already!”
In the meantime, if people want to incorporate fasting into their routines, experts say that a fast is not an excuse to discard healthy eating altogether.
“As I tell my patients, the point is not to eat all you can during the [eating] window, but use the window as a strategy to reduce total daily calorie intake, “says Catenacci.” However, future studies are needed before we can safely say that eating within time constraints, even with this mindset, is an effective weight loss strategy. “
Abstract:
IMPORTANCE: The efficacy and safety of time-restricted intake have not been explored in large randomized clinical trials.
OBJECTIVE: To determine the effect of a 16: 8-hour time-restricted diet on weight loss and metabolic risk markers.
INTERVENTIONS: Participants were randomized such that the constant meal timing (CMT) group was instructed to eat 3 structured meals per day, and the time-restricted eating (TRE) group was instructed to eat Optional from 12:00 PM to 8:00 PM and completely abstain from caloric intake from 8:00 PM to 12:00 PM the next day.
DESIGN, SETTING, AND PARTICIPANTS: This 12-week randomized clinical trial involving men and women ages 18 to 64 with a body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) of 27 to 43 was carried out on a personalized mobile study application. Participants received a Bluetooth scale. Participants lived anywhere in the United States, with a subset of 50 participants living near San Francisco, California, who underwent tests in person.
MAIN OUTCOMES AND MEASURES: The primary outcome was weight loss. Secondary outcomes for the in-person cohort included changes in weight, fat mass, lean mass, fasting insulin, fasting glucose, hemoglobin A1c levels, estimated energy intake, total energy expenditure, and energy expenditure. energy at rest.
RESULTS: Overall, 116 participants (mean [SD] age, 46.5 [10.5] years; 70 [60.3%] men) were included in the study. There was a significant decrease in weight in ERT (−0.94 kg, 95% CI, −1.68 to −0.20; P = 0.01), but no significant change in the CMT group (−0.68 kg, 95% CI, -1.41 to 0.05, P = 0.07) or between groups (−0.26 kg, 95% CI, −1.30 to 0.78; P = .63). In the face-to-face cohort (n = 25 ERT, n = 25 CMT), there was a significant decrease in weight within the group in the ERT group (−1.70 kg, 95% CI, −2.56 to −0.83 ; P <0.001). There was also a significant difference in the appendicular lean mass index between the groups (−0.16 kg / m2, 95% CI, −0.27 to −0.05; P = .005). There were no significant changes in any of the other secondary outcomes within or between groups. There were no differences in estimated energy intake between the groups.
CONCLUSIONS AND RELEVANCE Time-restricted eating, in the absence of other interventions, is no more effective for weight loss than eating during the day.
[ad_2]
