The 5:2 diet, a type of intermittent fasting, was found to be no more effective than traditional weight loss methods, according to researchers who conducted the first study of this regimen in a real-life setting.

However, the researchers found that the approach, which involves two days of heavily restricting calories (500 calories for women, 600 calories for men) and five days of sensible eating, was rated more highly by the obese individuals in the study because it was easy to follow. 

Doctors may want to consider including the 5:2 diet as part of their standard weight management advice to patients, she said.／Nepal Yoga Academy

Intermittent Fasting: Benefits and Limitations

“Here, we have been able to provide the first results on the effectiveness of simple 5:2 diet advice in a real-life setting. We found that although the 5:2 diet wasn’t superior to traditional approaches in terms of weight loss, users preferred this approach as it was simpler and more attractive,” said Katie Myers Smith, a chartered health psychologist and senior research fellow at Queen Mary University of London, in a news statement. She was an author of the study published in the scientific journal PLOS ONE.

Doctors may want to consider including the 5:2 diet as part of their standard weight management advice to patients, she said.

The study involved 300 obese individuals in Tower Hamlets, an inner-city area with high levels of deprivation in London. The participants were assigned to either follow the 5:2 regimen or a more traditional approach to weight loss, which emphasized consuming more vegetables and whole-grain foods, eliminating high-sugar and high-fat foods, reducing portion sizes, and engaging in regular exercise. 

‘Modest’ results

The results of both approaches were very similar and the study reported.

At six months, individuals following the 5:2 diet had lost an average of 1.8 kilograms (4 pounds) compared to 1.7 kilograms (3.7 pounds) for those following the standard diet advice. By the 12-month mark, the numbers were 1.9 kilograms (4.2 pounds) and 1.8 kilograms (4 pounds), respectively.

Some 18% of 5:2 dieters had lost at least 5% of their body weight after one year, compared to 15% of those using the conventional approach. 

Of the group following the 5:2 diet, half attended six group support sessions for the first six weeks after the initial information session. However, the study found that the impact of the group support diminished over time.

Participants were positive about the various weight loss approaches, but those following the 5:2 diet were more inclined to recommend it to others and expressed a higher likelihood of continuing with this approach.

The study was a randomized control trial, regarded as the most rigorous kind of research, and while the number of participants was larger than most previous studies of intermittent fasting, the authors said “some findings of borderline significance could have become clearer if the sample size was larger.”

The individuals who adhered to the traditional weight loss advice were also more inclined to experiment with other strategies like Weight Watchers, Slimming World, or other diets. This aspect might have obscured the effects, but according to the study authors, it would not have been ethical or practical to prevent participants from exploring alternative methods. 

The study was a randomized controlled trial, regarded as the most rigorous kind of research. While the number of participants was larger than in most previous studies on intermittent fasting, the authors mentioned that findings of borderline significance could have become clearer if the sample size was larger.／Pexels

Intermittent fasting

Some experts believe that alternating between fasting and eating can enhance cellular health by triggering metabolic switching.

In metabolic switching, cells deplete their fuel reserves and convert fat into energy, essentially transitioning from fat storage to fat utilization. According to a review of previous animal and human studies published in The New England Journal of Medicine, intermittent fasting can lower blood pressure, facilitate weight loss, and enhance longevity.

The method is not appropriate for everyone; particularly pregnant women and those with medical conditions such as diabetes or eating disorders.