Reward-related brain circuitry responded more to romantic images after the women participating in the study had eaten.
The study, published in Appetite, compared the reward response to romantic cues in women with a history of dieting to non-dieters.
"We found that young women both with and without a history of dieting had greater brain activation in response to romantic pictures in reward-related neural regions after having eaten than when hungry," reports first author Alice Ely, a postdoctoral research fellow at the University of California-San Diego School of Medicine.
Earlier studies had indicated that people are often more sensitive to rewarding stimuli such as food, money and drugs when they are hungry. However, this was not the case in the new study.
"This data suggests that eating may prime or sensitize young women to rewards beyond food," says Ely. "It also supports a shared neurocircuitry for food and sex."
Ely and her colleagues at Drexel University in Philadelphia, PA, had previously conducted a pilot study - published in Obesity - among college-age women that examined how the brain is affected by food cues, and whether these responses differed between historical dieters and non-dieters.
They discovered that women with a history of dieting responded more dramatically to positive food cues (such as chocolate cake) than those who had never dieted or were currently following a diet.
Historical dieters have been identified as being more at risk for weight gain, and so the researchers concluded that the area of their brains that is associated with reward may be more predisposed to desire food than those who had never dieted.
Findings consistent with previous research
Due to these findings, Ely and colleagues hypothesized that historical dieters are differentially sensitive to rewarding stimuli in general, and decided to test their theory by looking at brain activation when viewing romantic pictures compared with neutral stimuli in both fasted and fed states.
Using magnetic resonance imaging (MRI), the researchers discovered that among both historical dieters and non-dieters, the reward-related brain circuitry responded more to romantic cues after having eaten.
However, the neural activity in one region of the historical dieters' brains was significantly different to that observed in the non-dieters brains. Historical dieters were more responsive to romantic cues in the superior frontal gyrus when fasted and in the middle temporal gyrus when fed.
"The pattern of response was similar to historical dieters' activation when viewing highly palatable food cues, and is consistent with research showing overlapping brain-based responses to sex, drugs and food," Ely concludes.
According to the Boston Medical Center, an estimated 45 million Americans diet each year and yet, despite this, nearly two thirds of Americans are overweight or obese. Could neurological factors play a part in the prevalence of obesity?
Last month, Medical News Today reported on a study that found women who survive breast cancer are more likely to gain weight over the following years than women who have not had cancer, with survivors gaining an average of 3.6 lb more in weight.