Most strikingly, those who were on the lard diet for just a day suffered heart attacks that were 70 per cent smaller than those in the animals given normal food, the annual Experimental Biology conference heard.

University of Cincinnati researcher Lauren Haar said: ‘This shows that acute, or short-term, high-fat feeding in animal models does preserve cardiac function.’

It is unclear how short bursts of fat help the heart but it may be through boosting the amount of energy available to the heart muscle, aiding the healing process.