Now the brain circuitry in both hungry and satiated younger women has been explored in a study in the journal Appetite.

Some of the women had dieted in the past and some had never dieted.

In response to romantic pictures, MRI scans showed all the women had greater activation in the reward-related neural regions of their brain after eating compared to when they were hungry.

The authors, of Drexel University in Philadelphia, say this suggests eating may prime or sensitise women to rewards beyond food. It also supports the theory that food and sex share some neuro-circuitry.

The latest study grew out of a larger one published last year in the journal Obesity that investigated how the brain changes in response to food cues in college-aged women of normal weight.

It showed that after a meal the brains of women with a history of dieting responded more dramatically to positive food cues, such as chocolate cake. It seemed historical dieters were predisposed by their brain reward circuitry to desire food more than those who had not dieted.

The researchers then wanted to know if there would be a difference in the response to sex between hungry historical dieters and non-dieters

Both groups responded more to romantic cues when fed. The brains of historical dieters, however, also responded as they had to positive food cues, suggesting an overlap in circuitry between food and sex.