The bliss of the sun, the change of scenery... there’s something about holidays that makes us think we can overindulge without doing our waistlines much harm.

But just five days of eating more fatty food than usual can have a longer-lasting effect than we realise.

What’s more, it continues even after we return to our normal eating habits, a study has found.

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Eating fatty foods for just five days can change the body's metabolism for the worse, researchers discovered

Repeated blowouts could lead to weight gain, obesity and other health problems.

‘Most people think they can indulge in high-fat foods for a few days and get away with it,’ said Dr Matt Hulver, who carried out the study in the US.

‘But all it takes is five days for your body’s muscles to start to protest. This research shows our bodies can respond dramatically to changes in diet in a shorter time frame than we have previously thought.’

Five days of indulgence is enough to alter the metabolism, the study found, weakening our ability to process food effectively even when we do start eating healthily again.

Volunteers who ate a high-fat-diet for five days were less able to process sugar after the experiment was completed.

After five days of eating lots of fat, the muscles' ability to oxidise glucose (sugar) - one of the stages of breaking it down to use it into energy - was disrupted

Processing sugar in the muscles is one of the key ways that the body absorbs calories.

Dr Hulver, from the Virginia Tech College of Agriculture and Life Sciences, said: ‘There are plenty of times when we eat fatty foods for a few days, be it the holidays, vacations or other celebrations.

'But those high-fat diets can change a person’s normal metabolism in a very short time.’

During the study, which was published in the journal Obesity, healthy university students were fed a fat-laden diet including sausages, macaroni cheese and other food loaded with butter.

A normal diet is made up of about 30 per cent fat but the students were given a diet of 55 per cent.

They consumed the same amount of calories as before the study, but more came from fat.

Dr Hulver found the muscles’ ability to oxidise glucose was disrupted after five days of the high-fat diet. After we eat, our muscles break down glucose by oxidising it for energy or storing it for later use.