IRELAND'S leading nutrition body has said that a new fasting diet is promising, but requires a lot more research to establish if it is healthy.
Fasting diets where you eat 500 or 600 calories a day for two days a week and whatever you like the rest of the time have been sweeping Ireland in recent months.
The Irish Nutrition and Dietetic Institute (INDI) said yesterday that it was a hugely popular diet, but there was not enough medical evidence yet to endorse it as a weight-loss method.
INDI spokeswoman Sarah Keogh said that even though some short-term studies were promising, another 10 years of medical studies were needed to confirm if the diet was a healthy formula for weight loss.
"It's a fad, it's not the worst fad, but there haven't been long-term studies to show if people can follow it for a year or two years," she said.
Ms Keogh said it was extremely popular at the moment in the way the Atkins Diet had been a few years ago, but of the people she had encountered doing it, only one had followed it correctly, while others tended to overeat on non-diet days.
It was also possible that people who were already low on micronutrients such as calcium or iron would become further depleted by eating such a small amount on diet days.
"My advice would be don't do this if you're pregnant, diabetic or on medication, and if you are planning to do it take advice from a dietitian to make sure you don't miss out on vital nutrients," Ms Keogh said.
Fasting diets shot into the public eye last August when Dr Michael Mosley presented a 'Horizon' documentary claiming they had numerous health benefits in combating the effects of ageing – including weight loss.
This included lower chol- esterol and glucose levels and protection against Alzheimer's disease.
Dr Mosley pointed to a US study that showed that participants lost weight and did not gorge on off days, and said he himself had lost 19lb and avoided the need to go on cholesterol-lowering statins.
Since then a number of diet books such as 'The Fast Diet' and 'The 5:2' diet have become bestsellers in Ireland and Britain.
The diet involves a maximum 500 calorie allowance for women on two non-consecutive days and a maximum of 600 calories for men, with users free to eat whatever they like the other five days of the week.