Experts at the University of Bath found fasting diets increased the risk of infection by 20 per cent
Previous studies have found the 5:2 diet helps with weight loss, longer lifespans and lowering blood pressure
Fasting diets like the popular 5:2 regime may make you live longer, but experts have warned they could leave you more susceptible to infection.
The extreme diet, which involves drastically reducing calorie intake for two days a week, has been widely credited with weight loss, longer lifespans and lowering blood pressure.
But scientists at the University of Bath – who have spent the last year testing their theory on fruit flies – have warned the diets could lead to a 20 per cent increase in infections.
Experts discovered that the genes in flies which are activated by a fungal infection are very similar or identical to the genes activated in people when they restrict their diet.
Experts at the University of Bath have warned fasting regimes, like the popular 5:2 diets, may make you live longer but they leave people more susceptible to infections
When the flies were exposed to the fungal disease their lives were extended by around 14 per cent, but worryingly their susceptibility to infection increased by 20 per cent.
The scientists warned extreme dieters could be experiencing the same reaction to fasting as the flies do to the fungal disease, so should be aware of the ‘trade off’ when following the diets long term.
Dr Nick Priest, lecturer in biology and biochemistry who led the study, said: ‘Many studies have documented benefits of diet restriction, but there is a lack of data on levels of illness in people administered these anti-ageing treatments.
The new study found the risk of infection in fruit flies, rose 20 per cent when they were subjected to fasting
‘We know that certain stresses such as starvation or exposure to pathogens can extend life and increase fertility, but we have found that ironically this has a trade-off in terms of immune function.
‘Our findings are not all that surprising. We have known for decades that starved mice are more likely to succumb to serious infections.
‘But, there has been a lot more interest in the short term benefits than potential long-term costs.
‘There are clear health benefits to diets such as the 5:2 regime, but we need to bear in mind there are side effects.
‘It shows that even the fountain of youth should come with a warning label.’
Dr Priest and his team discovered three years ago that a fungal pathogen made fruit flies live 14 per cent longer by activating the same ‘stress’ and ‘immunity’ genes which responded to fasting in humans.
But for the last year they have used 30,000 flies to discover that the same flies become 20 per cent more likely to catch an infection than flies which were not exposed to the life-lengthening fungus.
He said more work needs to be done to establish why and how extreme diets leads to more infections.
He added: ‘This is the aspect that people haven’t studied.
‘We know that when we have friends that go on crazy diets there can be massive changes in physiology.
‘There is lots of evidence to say that in ideal condition animals live much longer with restricted diets calorie intakes, but our study shows there is a good reason for that – the trade off for that occuring is the suppressing of the immune system.’
Source: Daily Mail
