Intermittent fasting is sometimes promoted as a magic bullet to lose weight.
However, a new study found that this method is not as effective as traditional daily calorie restriction plans.
Intermittent fasting is an umbrella term for dietary restriction plans that follows different meal timing schedules for a period of time,
The “5:2” diet, alternate-day fasting and time-restricted feeding are examples.
In the past few years, fasting diets have become more popular with images of celebrities showing miraculous weight loss.
Yet, the benefits of intermittent fasting are not as strong as traditional daily calorie restriction.
The current research shows that people who followed a traditional diet lost more weight than those who were fasting, despite both eating the same number of calories.
For this study, participants were divided into three groups:
- Non-fasting dieting group: received 25 percent less calories across all meals every day.
- Fasting group: alternating 24-hour periods of complete fasting and eating 50 percent more than usual on non-fasting day.
- Fasting on alternate days: fasting one day then consuming 100 percent more than usual daily intake.
Prior to the study, all the participants had a typical diet of 2000-2500 calories every day.
During the study period, the average daily energy intake was reduced to 1500-2000 calories for the first and second groups.
The non-fasting group lost 1.9 kg in three weeks and body scans confirmed this amount of weight loss was completely from burring body fat and belly fat.
The second group lost 1.6 kg in three weeks but half this weight loss was from burning body fat and the other half was from losing muscle mass.
The third group, however, didn’t lose any weight.
Professor James Betts, the study’s lead author, said:
“Many people believe that diets based on fasting are especially effective for weight loss or that these diets have particular metabolic health benefits even if you don’t lose weight.
But intermittent fasting is no magic bullet and the findings of our experiment suggest that there is nothing special about fasting when compared with more traditional, standard diets people might follow.
Most significantly, if you are following a fasting diet it is worth thinking about whether prolonged fasting periods is actually making it harder to maintain muscle mass and physical activity levels, which are known to be very important factors for long-term health.”
The study was published in the journal Science Translational Medicine (Templeman et al., 2021).