Weight loss: Study finds calorie restriction more effective than intermittent fasting

Intermittent fasting involves eating only during specific time intervals. There are many ways to do intermittent fasting; this may mean not eating on certain days or only eating foods at certain times of the day. Some people are looking to use IF to lose weight or maintain a healthy weight.

Some evidence suggests that intermittent fasting can help people lose body fat and may help reduce the risk of type 2 diabetes and cardiovascular disease.

However, researchers are still working to understand the potential dangers of intermittent fasting and how to weigh those risks against the potential benefits. Overall, this is an area where more data is needed.

Beata Rydyger, a licensed nutritionist based in Los Angeles, Calif., and clinical nutrition consultant at Zen Nutrients, who was not involved in the study, highlighted the challenge of studying eating behaviors for Medical News Today:

“In general, diets are more difficult to study because dietary changes do not have an immediate effect on health. Most study participants have trouble keeping track of what they eat, and few can diet long enough for the beneficial effects to be measured.

“Proponents of intermittent fasting point to a range of potential benefits, some of which are backed by research, including improvements in weight loss, thinking and memory, type 2 diabetes, health fabrics and even physical performance.”
— Beata Rydyger, nutritionist

This study included 547 participants recruited from three different health systems.

The researchers gathered information about the participants through electronic health records and the use of a specialized mobile app called Daily24. Participants could log when they ate, meal size, when they went to bed and when they woke up.

For each recorded meal, participants rated the meal size as less than 500 calories (small), 500 to 1,000 calories (medium), or more than 1,000 calories (large).

Study author Dr. Wendy Bennett explained her research methods for DTM:

“We designed an app to collect the ‘time to eat’, and when participants captured the time, we also asked them the size of the meal (small, medium or large). Participants from 3 health systems used the app for 6 months. We linked app data with survey data with electronic health records. »

Dr Bennett said they then analyzed the link between eating intervals, including participants’ total eating window, the time between waking up and going to bed, and the time between their last meal and bedtime. bedtime, with weight changes over about six months. years.

The researchers found that the timing between the first meal of the day and the last meal of the day was not associated with weight changes. However, they found that eating more frequent and larger meals was associated with weight gain.

“The main clinical implication is that restricting your eating window (i.e. eating over less time, having more fasting time) may not reduce weight gain over time. So what to eat more medium or large meals are associated with weight gain over time, and more smaller meals are associated with weight loss over time.
— Dr. Wendy Bennett

In some of their analyses, the researchers found that eating earlier after waking and having more time between a last meal and bedtime may be associated with less weight gain.

Dr. Katherine Saunders, co-founder of Intellihealth and Obesity Physician who practices at Intellihealth’s telemedicine practice, Flyte Medical, who also was not involved in the study, noted DTM that the main finding was not surprising.

“The investigators found an association between eating more frequent and larger meals and weight gain, suggesting that total overall calorie intake is the primary driver of weight gain. This is not surprising” , she said.

“What is more interesting is that the participants with [a] a shorter time between waking and the first meal and with a longer time between the last meal and sleeping seemed to experience less weight gain, a trend suggesting that eating earlier in the day may aid weight control.
— Dr. Katherine Saunders

Data on intermittent fasting is still emerging, so no single study offers full evidence that the method is effective or ineffective. This particular study also had several limitations to consider.

First, the researchers were only able to analyze data from study participants who downloaded and used the Daily24 app. This exclusion may have had an impact on the study population and results.

They only recruited participants from three health systems, which means that the results cannot necessarily be generalized. Almost 78% of participants were female and white, indicating the need for more diverse future studies.

The study also had a relatively short follow-up time, which resulted in fewer weight measurements and lower measurement accuracy. The researchers were also unable to measure participants’ intentions to lose weight before they entered the study.

The way the researchers measured meal times couldn’t assess more complex fasting methods. The data was also based on participants’ self-reporting, and the foods were not standardized or rated for quality.

“This study did not specifically assess regimens such as intermittent fasting. We also did not assess diet quality for the meals reported in the app,” Dr. Bennett told DTM.

“Randomized controlled trials that adjust calorie intake are needed to further test the role of eating timing in preventing weight gain and also in weight loss,” she added.

This study indicates that other weight loss methods may be more effective than intermittent fasting. Regardless of weight goals, people can use a variety of methods to stay healthy and manage their weight.

For some, this might mean incorporating intermittent fasting, but others may choose different strategies. Dr Bennett said self-monitoring was the key to weight loss.

“Other studies show that people might be able to use time-restricted eating or intermittent fasting to help them reduce calorie intake and thereby lose weight, so it may still be a tool helpful weight loss plan for some people who can stick with it.. The cornerstone of weight loss continues to involve self-monitoring,” she said.

Dr. Saunders further noted that people react differently to different weight loss methods and that this is not a one-size-fits-all approach.

“There are so many factors that affect weight regulation that successful weight loss must address all of these factors in a personalized way. There is no ‘best diet’ and different people respond differently to any approach to weight loss. weight loss, whether it’s a diet, an exercise routine, anti-obesity medication, or even bariatric surgery.”
— Dr. Katherine Saunders