For millions of men with troubles in the bedroom, pills such as Viagra are usually the first port of call.
Yet many could achieve the same results simply by skipping lunch or dinner two to three times a week, research suggests.
Scientists found that intermittent fasting substantially reduced a man’s risk of impotence.
Those regularly missing meals were twice as likely to have a healthy love life, they found.
They think occasional calorie restriction reduces damage to the body’s circulation which can lead to problems performing.
One in ten men in the UK suffers erectile dysfunction at some point. Some studies suggest more than a third of those over 40 are affected.
Although drugs such as Viagra have revolutionised treatment, around 35 per cent of men who take them see no improvement.
A healthy diet and lifestyle are known to boost energy levels and sustain a strong libido.
Experts at the University of California Irvine compared different dietary approaches to see how they affected men’s sex drive.
They looked at erectile function in men who were vegetarian or vegan, those who stuck to organic, whole food or low-fat diets, and those who fasted regularly.
Intermittent fasting has become a hugely popular weight loss remedy in the UK in recent years.
One of the most high-profile techniques is the 5:2 diet, where calorie intake is normal for five days of the week – at 2,500 for men and 2,000 for women – but restricted to 500 to 600 calories on the remaining two days.
The researchers tracked 271 middle-aged and elderly men over a year.
The results, published in the journal Urology, revealed those indulging in intermittent fasting were twice as likely to be free of erection problems as men who were vegan or vegetarian, or who had whole food or low-fat diets.
The scientists said they cannot be sure fasting is the secret, rather than other healthy lifestyle measures.
But they added: ‘Intermittent fasting has been shown to improve blood sugar control, a risk factor for type 2 diabetes – a common cause of erection problems. It may also boost testosterone.’
Dr Geoff Hackett, chairman of the British Society of Sexual Medicine, said fasting for a couple of weeks is unlikely to help.
‘It may depend on how long you do it for,’ he said. ‘And it may also be more likely to work if you intermittently abstain from alcohol as well.’