Everyone knows that dieting and losing weight is hard, especially for women. It's like our bodies are hard-wired to fail - and, perhaps they are. At least that is one interpretation of a new study coming out of the Brookhaven National Laboratory this week, set to be published in PNAS shortly.
The researchers looked at the PET scans of men and women after 20 hours of fasting at rest, when looking, smelling, and drooling over their favorite food, and when that food is presented to them but they are told not to think about it. All of the subjects reported feeling less hungry for the food when they tried not to think about it, but their brains told a different story.
The scans to the right show the differences in brain activity between the conditions of wanting the food and wanting the food but forcing themselves to think about something else. The top row is the women, and the scans aren't colored because there was no difference between the conditions. Whether they tried to distract themselves or not, their brains activated the same areas involved in the emotional regulation, conditioning, and motivation to eat. The second row, instead, are the men's scans - the blue areas are parts of the brain which were significantly less active when forcing themselves not to think about the food. The third row compares the women and the men, with the orange areas indicating where men showed decreases in brain activity that the women didn't.
In other words, when the men tried not to think about food, they succeeded in changing their brain chemistry and actually decreased their desire for it, while the women didn't. This might explain why it always seems easier for guys to lose weight - when they put their mind to it, it listens. This study is the first that has found gender-specific differences in the connection (or lack thereof) between emotion state and brain activity.
“The finding of a lack of response to inhibition in women is consistent with behavioral studies showing that women have a higher tendency than men to overeat when presented with palatable food or under emotional distress... This decreased inhibitory control in women could be a major factor contributing to the observed differences in the prevalence rates of obesity and eating disorders such as binge eating between the genders, and may also underlie women’s lower success in losing weight while dieting when compared with men," said lead author Gene-Jack Wang in the lab's press release.
Researchers think that the differences found may be due to sex hormones like estrogen, which have already been shown to affect weight, fat distribution, and even caloric intake. Other molecules that regulate eating behavior might also be involved, and clearly further research into this effect is needed.
In the meantime, we women can honestly complain that it's not our fault we can't shed those holiday pounds. After all, you boys have it easy - your brains actually forget about food when you want them to. Stupid men... why must women always have the short end of the stick?
PS I'll post the link to the article when it gets published...