Its an often trotted out line that women love chocolate and that a (large) percentage prefer it to sex. Without offending the performance of the womens other half, there may be another (or at least partial, other half's, you're not off the hook yet) explanation.
Two recent studies that at first glance do not seem related, are inextricably joined at the hip, at least to my little brain.
The first study showed that dieting is linked to lasting alterations in stress hormone patterns, including prolonged gene expression that continues after the diet.(1) These alterations in the brain likely promote binge eating and cravings for high fat or high carbohydrate foods once the diet is done. This is the first clear evidence that yo-yo diet patterns are likely related to stress hormones and stress gene expression.
Despite the health risks associated with being overweight, low-fat and low-carbohydrate diets are notoriously difficult to maintain over long periods. Most individuals, especially those who lose weight at more than about two pounds per week, regain the weight lost. This pattern occurs with all the calorie restriction strategies offered by diet centers and online food plans. The evidence is stacking up to show that successful weight control may hinge more on controlling stress. There are numerous studies showing that even people of normal weight eat high-fat and high-sugar foods to relieve stress.
The second study suggested that women become addicted to cocaine more easily than men and find it harder to give up. It appears that the motivation of female rats to work for cocaine is much higher than males.
Researchers from the Molecular and Behavioral Neuroscience Institute, University of Michigan, found that rats bred to have an elevated stress response and increased impulsiveness are more easily trained to reward themselves with cocaine.(2) They are also more determined, than similar rats with low impulsivity and lower stress responses, in pursuit of their next fix.
While cocaine dependency has something to do with thrill seeking and impulsivity, it is also affected by the differences between males and females. At a low dose, for both sets of rats, it was the females who were quickest to learn self-administration and were the most willing to work harder for their next fix. At higher doses, the differences in behaviour between the male and female rats were less obvious.
The link? Both the studies focused on subjects that were either bred to evoke an elevated stress response or were environmentally stimulated to express the same genes. In an attempt to control their genetic response the high-stress individuals used various substances to create a chemical support system. As I've shown in previous articles, there are many ways to alter body chemistry, especially in the brain. In the above studies the stimulants sought out by the subjects were cocaine, sugar and chocolate, all three stimulating neurotransmitter release, principally Dopamine.
The evidence shows that females need to be careful how they approach weight loss as they are genetically predisposed to a high-stress response and the subsequent associated behaviour anyway, and the usual dieting strategies are a sure-fire way to realise this genetic heritage.
References:
1. Nature Reviews Neuroscience, 12, 65 (February 2011), doi:10.1038/nrn2985.
2. Jennifer A. Cummings, Brooke A. Gowl, Christel Westenbroek, Sarah M. Clinton, Huda Akil, Jill B. Becker. Effects of a selectively bred novelty-seeking phenotype on the motivation to take cocaine in male and female rats. Biology of Sex Differences, 2011; 2: 3
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