Intermittent fasting ‘no better for weight loss’ than calorie counting

Time-restricted eating, commonly known as intermittent fasting, may produce similar weight loss results for adults with obesity compared to traditional calorie counting, according to a new study.

The small clinical trial, whose results were published on Tuesday in the journal Annals of Internal Medicine, found that participants who engaged in 8-hour time restricted eating had improved insulin sensitivity compared to those in the control group who ate their calories any time over 10 or more hours a day.

Over a billion people worldwide are obese with the with the disease projected to grow in prevalence across the globe, according to the World Health Organization.

Obesity has also been found to be a serious risk factor for other metabolic diseases such as type 2 diabetes, heart disease, and some types of cancer.

A widely adopted tried-and-tested method to lose weight is to burn more calories than one consumes, and to achieve this, individuals typically count the calories of the food they eat each day.

While this traditional approach for losing weight involves counting calories, time-restricted eating, without calorie counting, has also emerged as a popular strategy as it is easier to follow.

However, whether intermittent fasting is as effective in producing weight loss, especially beyond the short term, has remained unclear.

In the new research, scientists from the University of Illinois Chicago studied 90 adults with obesity from the Greater Chicago area to determine whether intermittent fasting or calorie restricted eating would be more effective for weight control and heart disease risk reduction.

Researchers randomly assigned participants to 1 of 3 groups: 8-hour time-restricted eating from noon to 8:00 pm only without calorie counting; reducing a fourth of their calories daily; or no change in calorie consumption with eating taking place over 10 hours or more throughout the day.

Participants who followed time-restricted eating and those adopting calorie restriction met regularly with a dietician.

The study found that participants who engaged in time-restricted eating ate 425 fewer calories per day than the control group and lost about 4.5kg (10lb) more than the control group after one year.

On the other hand, the calorie-restricted group ate 405 fewer calories per day and lost about 5.5kg (12lb) more after one year, with participants in both groups showing high adherence to their interventions.

Scientists believe the new study and its findings can help make better-informed clinical decisions by taking individual preferences into consideration, rather than just choosing a diet that may be more effective.

Researchers also point out that access to dieticians likely helped the participants make healthier food choices.

As there was substantial individual variability in weight loss among participants using these interventions, they called for further research to determine who would most benefit from each of these diet choices.