Catenacci notes that this study is another reminder of the critical need to “rigorously evaluate weight-loss interventions such as time-limiting eating before recommending them to the general public” She acknowledges that there are still many questions when it comes to this way of eating and says the study does not “close the door on time restriction eating as a weight-loss intervention or as an intervention that can lead to other positive effects including longevity.
We know diet plays a crucial role in the ever-evolving pursuit of longer and healthier lives. Scientists have also concentrated in recent years on the potential of intermittent fasting — a diet regimen that relies on when and not what you eat.
New research however shows that it can’t deliver on what some intermittent fasts are looking for when they adopt it as an eating pattern.
Intermittent fasting is also billed as a simple strategy to lose weight — no counting calories, complicated recipes or a specific food group involving.
But recently, researchers examined in one of the most rigorous studies on eating patterns 116 obese and overweight individuals over three months to see if scientific evidence lived up to hype.
The team in turn found that time-restricted eating or intermittent fasting did not help people lose weight significantly more than just consuming three meals a day. Instead, it had an unintended side effect: the loss of muscle mass
Can intermittent fasting really help you lose weight?
A. R. W. Morris is one of the co-authors of the study and a cardiologist at the University of California, San Francisco. His team released their results, published in the journal JAMA Internal Medicine on Monday.
Prior to this work, Weiss ate Time Restricted Imitation for the past. After analysing these results he stopped.
There was no weight loss after time-restricted eating (about.2 pounds per week on average over 12 weeks), weiss tells Inverse. It did not provide any other metabolic advantage. And then there was the worrying sign over the loss of Lean Mass”
Endocrinologist and metabolic expert at the University of Colorado says that the study was well executed, but says factors such as the timing of the eating window, lack of behavioral support and decreases in physical activity could have impacted the results. Catenacci was not involved in the study.
This well-designed study demonstrates that late time restriction eating alone without behavioral support does not result in clinically meaningful weight loss over 12 weeks, according to Catenacci in reverse. She notes that this study is another reminder of the critical need to “rigorously evaluate weight loss interventions, such as time-limiting eating, before recommending them to the general public”
Catenacci also acknowledges there are still many questions that exist when it comes to this way of eating, and argues the study doesn’t “close the door on time-restricted eating as a weight-loss intervention or as an intervention that can lead to other positive effects including longevity.
What the study examined — To determine how intermittent fasting or time restricted eating impacts weight and metabolism, Weiss and his team recruited a group of 116 people who were classified as overweight or obese.
The researchers divided the group into two eating patterns. Half practiced day-time-restricted eating — eating all of their meals between noon and 8 p.m., then fasting for 16 hours. Outside of the dining window, only non-caloric beverages were permitted.
The other half ate three meals a day including snack. Neither the group received instructions on what or how much to eat during the day. They were also not given instructions to workout or to stop exercise either.
Over three months, researchers tracked both the weight and metabolic outcome of the group using a mobile app, survey data and a Bluetooth scale. Each participant weighed in the morning every morning before eating or drinking.
The results and explanation — Researchers predicted that the group had more weight loss than the group of three meals a day. But over 12 weeks, there was no more weight loss compared with time restricted eating compared with the regular meal group.
There were also no significant observed differences in fat mass, fasting insulin, blood glucose, HbA1C or blood lipids between the two groups.
Catenacci says: “The minimal weight loss suggests they did not achieve a significant energy deficit. “I think that this suggests that there is nothing magical about a late-time-restricted eating window for short-term weight loss. ”
Over the course of the study, the fasting group members lost about three and a half pounds. However, the bulk of lost pounds was not fat.
Essentially it was a low mass, including muscle. About 20 to 30 percent of the total weight loss is usually lean mass. The relative size of the lean mass loss in this study was 65 percent.
You don’t want to lose mass in leanness. You want fat loss,” says Weiss. “Hier we discovered that two-thirds of weight loss came from a less than lean mass.
There are a number of possible factors that can drive fasting participants to lose their muscle mass, one is that it is possible that participants were not eating enough protein or putting enough physical activity into their diet. Fasting participants walking daily walked about 2,500 fewer steps than day – a shift in activity that could contribute to their unchanged weights and dwindling lean mass.
It’s also possible that a later morning fast didn’t curb energy intake, which would lead to weight loss.
Preclinical data suggests that an early calorie restriction window may have greater metabolic benefits and that practicably a early calorie restriction window may be more likely to result in greater caloric restriction as most people currently consume the majority of their calories later in the day and in the evening, explains Catenacci.
In the future, she suggests that rigorous trials be necessary to evaluate other intermittent fasting nuances, like eating earlier in the day or combining it with a reduced diet.
What is next for intermittent fasting — After publishing, Weiss and his team released the study immediately – with experts sharing the results on social media. Some argue that the participants did not show a real benefit, either in the day or early enough to get a quick result. Others argue that the eating pattern should be combined with other diets to see weight loss results.
The trial shows what many nutrition and exercise studies do — that there is no single solution or magic strategy to lose weight and live a long healthy life.
This is just one regimen but it shows how easy it is to think something works when it doesn’t, says Weiss. “Or maybe better yet, that everything works”
Weiss does not conclude that the results mean that there will be some kind of major effect of fasting, says.
Longevity? “Who the hell knows?” Weiss says. “Weight and metabolic endpoints are difficult enough!”
In the meantime, if people do intend to include fasting into their routines, experts say that a fast is not an excuse to completely reduce healthy eating.
As I tell my patients, the point is not to eat what you can during the window to consume, but to use the window as a strategy to reduce the daily total calories, Catenacci says. “Nevertheless, future studies are needed before we can declare confidently that time restricted eating, even with this mindset, is an effective weight loss strategy.