Many diets come and go, like fads in the night, but there are those that gain considerable traction within certain groups and survive long enough to join the pantheon of self-discipline and denial from which each new batch of would-be weight losers have to take their pick.
The 5:2 diet, in which you fast for two days of the week and pretty much eat normally for the rest of time, has become a modern classic.
A wide range of celebrity and public figures from Beyonce, Jennifer Lopez, Benedict Cumberbatch (as if he needed to), Liv Tyler and Paul Schofield to Chancellor George Osborne and ex Bank of England Chairman Mervyn King have all extolled its virtues at one time or other.
The theory is that it is easier to abstain (although you should ensure you get your 500/600 calories on the fasting days, depending whether you’re male or female) than to reduce.
Is there any scientific evidence to support it?
A team from the University of Melbourne decided to put the diet to the test through a randomised research study using 24 obese male army veterans aged between 55 and 75.
Half of the group were put on a 5:2 diet restricting their calorie intake to 600 on two non-consecutive days of the week and allowing them to eat normally on the other days.
The other group had their normal daily intake (which averaged at 2,400 calories) cut by 600 to 1,800 calories a day.
Each subject was monitored over a six month period and was given five counselling sessions with a dietitian during the course of the study.
At the end of six months both sets of men had lost body fat and girth.
The calorie reducers lost 5.5kg (just over 12lbs), reduced their body fat by an average of 2.3% and their waistline by just over 6cm.
The 5:2 dieters lost 5.3kg (just over 11.5lbs), an average of 1.3% of their body fat but reduced their waistlines by 8cm.
Weight loss for both groups slowed down after the first three months which was also when the meetings with the dietitian stopped leading the researchers to conclude that support and encouragement are possibly more important factors in maintaining a diet than the form of the diet itself.
Most nutritionists would agree that reducing the number of calories and switching to healthier foods is the most beneficial way to lose weight, along with exercise.
The way in which a diet suits each individual temperamentally, however, can have an important bearing on its outcome.
Weightwatchers famously uses the scrutiny of fellow dieters to motivate its members.
In the Melbourne study the 5:2 group complained far more about hunger pangs than the calorie counters and perhaps it is that tangible feeling of self-denial that can be a motivator.
After all, in the absence of actually feeling good about ourselves and our health, which is surely the aim of any diet, we can at least feel good about our effort to get there.
Whatever the surveys say, if it works for you and helps you to stay healthy, go for it.
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