5:2 diet

The 5:2 diet, or fast diet, is a fad diet which stipulates calorie restriction for two days a week and eating an unmoderated amount for the other five days. A form of intermittent fasting, it originated and became popular in the UK, then spread to the rest of Europe and to the US.

Proponents of the diet claim it causes weight loss and has some beneficial effects on health; however as with other fad diets these claims are not supported by high-quality evidence.

The diet specifies a low calorie consumption (sometimes described as "fasting") for two days a week but allows unmoderated eating for the other five days. Men may eat 600 calories (2,500 kJ) on fasting days, and women 500 calories (2,100 kJ).

Proponents say that fasting for only two days a week may be easier for dieters to comply with than daily calorie restriction.

In general there is a lack of research evidence on intermittent fasting, and there is only limited evidence of the 5:2 diet's safety and effectiveness.

According to NHS Choices, people considering the diet should first consult a physician, as fasting can sometimes be unsafe.

In the UK, the tabloid press has reported on research claiming the 5:2 diet could reduce the risk of breast cancer; however according to the NHS the evidence being considered formed an inadequate basis for making such statements.

The diet became popular in the UK after the BBC2 television Horizon documentary Eat, Fast and Live Longer written and presented by Michael Mosley was broadcast on 6 August 2012 and many books on the diet quickly became bestsellers, soon after.

Dieticians and the UK National Health Service have categorized it as a fad diet.

A news item in the Canadian Medical Association Journal expressed concern that promotional material for the diet showed people eating high-calorie food such as hamburgers and chips, and that this could encourage binge eating since the implication was that "if you fast two days a week, you can devour as much junk as your gullet can swallow during the remaining five days".

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Wikipedia