From a piping hot bacon sandwich to an apple pie baking in the oven – just imagining eating these treats can make the mouth water.

And how vividly we conjure up the smell of these foods in our minds could influence how much we weigh, according to a new study.

Over two separate trials, researchers found that the stronger a person’s mental imagery of food odours, the higher their body mass index (BMI).

Scientists found that the stronger a person’s mental imagery of food odours, the higher their body mass index

It’s not clear exactly why this effect occurs, but it could be that vivid thoughts increase our cravings for food, and subsequently our consumption of them.

‘Mental imagery is an important factor in eliciting and maintaining craving,’ said the researchers, from Yale University School of Medicine.

‘Since food cravings occur more often in obese than normal weight individuals, we reasoned that ability to image might promote cravings and therefore be associated with BMI.

‘Supporting this possibility, we found that in two independent samples, participants with higher BMI reported greater perceived ability to image.’

Experts believe vivid thoughts increase our cravings for food, and subsequently our consumption of them

For the first part of the study, which was published in the journal Appetite, the researchers asked 27 people to complete three questionnaires that measured their perceived mental imagery ability.

The first two questionnaires showed how vividly the participants could evoke images or smells of non-food items.

The third questionnaire focused specifically on food.

Participants were asked to imagine the taste and smell of items such as freshly baked bread, biscuits, popcorn and barbecued food and to rate the created mental image on a scale.

The participants also had their weight and height measured, to obtain their BMIs.

‘As predicted, correlation analyses revealed positive associations between BMI and perceived ability to image odours and foods, but not visual objects,’ the researchers said.

They then carried out a further study, with another 57 participants, which achieved the same results.