The 5:2 diet appears to be everywhere these days. Celebrities ranging from Australian super-model Miranda Kerr to Chancellor of the Exchequer George Osbourne have claimed that the regime of fasting for two days out of every seven has helped them lose weight. But what are the fitness ramifications of eating fewer than 600 calories twice a week and what role does exercise have to play when doing a ‘Fast Diet’?

It was only in late 2012 that the 5:2 diet began to come to prominence and so there is relatively little scientific research into what positive or negative effects the diet might have on your overall fitness. However, the general consensus is that it will help you lose weight; one study found that it was as successful as calorie-controlled diets in reducing the weight of overweight young women. Yet the lack of empirical research leads us to look at anecdotal evidence: Max Anderton at Men’s Fitness found that as a result of doing the diet he went on carb binges on the days that he didn’t fast, which lead to his weight actually increasing by almost a kilo. Binging like that is not recommended, even though some claim on non-fast days you can eat whatever you like.

What is recommended is combining the diet with exercise. But whilst exercise on the ‘normal’ days is relatively straightforward, questions arise about whether or not to exercise on the ‘fast’ days. The NHS warns that the fasting ‘may affect your ability to exercise which is an important part of maintaining a healthy weight’. However, Michael Mosley – the 5:2 diet guru – suggests that those who exercise on days when they are fasting ‘burn more fat’, before warning that it’s best not to undertake endurance training on a fast day. The general consensus when it comes to exercising on fast days is if you ever feel uncomfortable stop. Also it’s worth noting that if you do chose to exercise on a fast day that does not mean that you can eat more calories, as is the way with some calorie-controlled diets.

The 5:2 diet isn’t for everyone. Some people cannot cope with the hunger of the fast days and prefer other forms of dieting. The decision to lose weight – and what method works for you – is always down to the individual. Here at Fitness Matters we can help to create a nutrition and fitness plan that suits your body. But whatever you decide, exercise is always essential when it comes to living healthily.

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