Researchers say just thinking that you’re full up will reduce cravings for snacks 

For those who struggle to keep away from the biscuit tin, there could be a calorie-free way to satisfy your hunger.

Simply thinking back to lunch, and imagining you ate twice as much as you did, can help to reduce snacking, scientists suggests.

The memory of a huge meal, even if it is false, could make people believe they are full. Researchers gave 151 people a standard-sized lunch before starting the study three hours later.

The volunteers were split into five groups, with one group asked to imagine eating twice the amount of lunch until they were ‘so full you could hardly move’.

They were then given biscuits, and allowed to eat as many as they liked. Those who imagined having had a huge lunch ate almost a third fewer biscuits – around 122 fewer calories.

Dr Joanna Szypula, from the University of Cambridge, wrote in the journal Appetite: ‘Thinking about lunch makes people more aware of the feeling that they are still full.

‘And imagining that they ate twice as much may further trick them into eating less.

‘It is further evidence that how much we eat may be more greatly controlled by our minds than our stomachs.’

Before the study, which is published in the journal Appetite, people were given a lunch of rice and sweet and sour vegetables.

When, three hours later, they were given a selection of chocolate chip cookies, chocolate fingers and digestives, people were told it was so they could rate them on qualities like crunchiness and saltiness.

The volunteers thought they were helping researchers understand how mood affected the taste of biscuits, but the researchers secretly wanted to watch how much of the snacks they ate.

After previously being asked to imagine they had eaten a lunch which was twice as large, people ate 51 grams of biscuits on average.

Volunteers who imagined having had a huge lunch ate almost a third fewer biscuits – around 122 fewer calories

That was well below the 75 grams of biscuits consumed by two groups of people asked to do an unrelated task – looking at a picture of spaghetti hoops or stationery and imagining them moving on a plate.

Other strategies, of remembering lunch and thinking about it moving on a plate, or remembering lunch in detail, including the actions of chewing and swallowing, did not significantly reduce people’s biscuit intake.

But people who imagined eating twice as much at lunchtime ate the equivalent of about four and a half fewer chocolate fingers, just over two fewer chocolate chip cookies or one and a half fewer digestive biscuits.

The tactic worked so well that some said they felt a bit sick after imagining eating a very large lunch.

They listened to a recording of less than two minutes which contained instructions including: ‘Recall the size of the rice and sauce portion you received. Now, imagine that it was twice as big.

‘Take a few seconds to imagine this. Now picture yourself eating both of these portions of rice and sauce.

‘Imagine physically doing the eating, the chewing and the swallowing.

‘Remember what you felt like after you finished eating your rice. Imagine you felt very full, so full you could hardly move.’

Dr Szypula said: ‘The next goal in our research is to find out if recalling recent meals and imagining having had a larger lunch can actually help people to lose weight.’