In recent years, so-called intermittent fasting – going without food for a certain amount of time – has become quite popular. However, a study published in the Journal of the North American Heart Association found that the practice may not be effective for weight loss. Instead, researchers have found that traditional calorie restriction, without the need for fasting, is the right approach to weight loss.
The study was conducted by researchers at the Johns Hopkins University School of Medicine in Baltimore, USA, on 550 adults. The participants’ average body mass index (BMI) was 30.8, a measure that characterizes obesity. The scientists had access to these people’s medical records, with weight records for each of them over an average of six years and three months.
The team built a mobile app, Daily24, to allow participants to catalog sleep, eat and wake times for each 24-hour window in real time. Emails, text messages, and cell phone notifications encouraged volunteers to use the system as much as possible. Based on the information, the researchers were able to measure how much time passed between the first and last meal of the day, how many hours each person went without eating after waking up, and the interval between the last time they ate. ate something and time to go to bed.
The analysis showed that mealtime did not correlate with weight change during the follow-up period. The total daily number of large (consisting of more than 1,000 calories) and medium (estimated to be between 500 and 1,000 calories) meals was associated with an increase in BMI over six years. Those who ate small meals (less than 500 calories) and in smaller quantities per day were able to lose weight.
“While previous research has suggested that intermittent fasting can improve body rhythms and regulate metabolism, this large group study with a wide range of body weights found no such link,” says senior author Wendy L. Bennett, a professor at Johns Hopkins University. Medical School in Baltimore. “Large-scale, rigorous clinical studies of the relationship between intermittent fasting and long-term weight change are extremely difficult to conduct. However, even short-intervention studies can be invaluable in helping guide future recommendations,” she points out.
Lead author Di Zhao, Ph. weight, plus even if the timing of meals, the results failed to demonstrate a direct relationship of cause and effect. “Future studies should include a more diverse population, since the majority of participants in the current one were highly educated, white women in the Mid-Atlantic region of the United States,” the authors note in the article.
Calculation
Specialist in weight loss and longevity, doctor Hugo Gatto points out that it is not possible to lose weight without consuming more calories than you consume. “Counting calories and achieving a calorie deficit (eating less than your body expends) is a non-negotiable weight loss strategy. What often happens is a calorie deficit much greater than necessary, i.e. the patient starves and fails to follow the strategy,” he says. “The best strategy, therefore, is a calorie deficit according to one’s needs and routine, so that the patient can apply and achieve lasting results,” he advises.
Nutrilogist Marcella Garcez, director of the Brazilian Association of Nutrology (Abran), points out that intermittent fasting is not a one-size-fits-all strategy, with risks of hypoglycemia, malnutrition, dehydration and weakness, among others, if performed without follow-up Also, previous studies have shown that it can improve weight loss, but calorie reduction may be the key. In some cases, fasting can lead to faster weight loss if participants cut as much as 500 calories per day. day. This means that the reported weight loss may be linked to calorie restriction rather than intermittent fasting,” she says.
Three questions for…
Professor at Johns Hopkins University School of Medicine in Baltimore
Wendy Bennett, a professor at the Johns Hopkins School of Medicine
(photo: Johns Hopkins/Disclosure)
Some studies have found an association between intermittent fasting and weight loss, while others, like the current one, have found no benefit. What could explain these discrepancies?
The discrepant results may be due to a lack of standardized ways to define or measure eating behaviors and the timing of eating. It is also possible that different study designs or different adjustments for potentially confounding factors, as a means of controlling for bias, contribute to the differences in results. To avoid discrepancies, there will be a need for well-designed randomized controlled trials.
Is it possible that intentionally fasting, not just when you sleep, has any benefit?
Fasting is equivalent to narrowing the window for eating, because when you don’t eat, you fast. We were unable to address intention to fast in this study. We asked participants to use an app to log when they ate, but we didn’t ask if they intended to fast for long periods without eating.
From a clinical point of view, what are the main implications of the article?
The main implication is that limiting your eating window (ie eating in a shorter time, having more time fasting) may not reduce weight gain over time. Eating fewer bulky meals is associated with less weight gain over time. Other studies show that people can use time-restricted eating or intermittent fasting to help them reduce their calorie intake and thus lose weight. Therefore, fasting can still be a useful weight loss tool for some people who decide to stick with it.
