This new study may help explain why women polish off the sweets, especially during PMS or menopause, says lead researcher Lisa A. Eckel, PhD, a behavioral psychologist in the Florida State University Program in Neuroscience.
Results of her new study — conducted on rats — appear in the November issue of American Journal of Physiology. They suggest that something besides willpower — or lack of it — is at work in females of both rats and humans, she tells WebMD.
"It may be that the female hormone estradiol promotes this craving for sweets," Eckel says. Studies of human cravings have shown increased yearning for chocolate during the menstrual cycle, she notes.
Setting Up the Buffet
In her experiments, Eckel first monitored a group of rats' regular eating patterns when they got a standard diet. No exercise was allowed in this part of the study.
Then, she gave them a standard diet as well as sweetened condensed milk — an ingredient in many desserts and known to be favored by rats, too.
Both male and female rats lapped up the milk. However, the female rats gobbled more milk, getting 35 percent more calories, compared with the males' 10 percent to 15 percent more calories. The rats also gained weight — 30 percent gain for females, 10 percent for males.
When allowed to exercise, both male and female rats cut back on overeating. Male rats cut back to their original intake. However, female rats cut back only about 20 percent.
Also, male rats jumped back into their regular exercise schedule. "But female rats did not — even though female rats are known to be much more active than male rats," says Eckel.
Moral of the Story
"It's a big leap from rats to humans; after all, humans are impacted by social and environmental factors," Eckel tells WebMD. "But this animal data suggests that females have a preference for high-carb, sweet foods — which may encourage or promote over-consumption of those foods."
What's driving this preference is unclear, she says. "We're investigating whether the female hormone estradiol plays a role, and some data suggests it may affect sweet tastes. ... There are lots of studies looking at preferences for sweets vs. fats across the menstrual cycle that may be driven by estradiol."
"I see it all the time — men may overeat, but they eat more servings of meat, fast food, or salty things. They just don't eat as many sweets as women do," says Darlene Allen, RD, a nutritionist and educator with the Duke Diet and Fitness Center at Duke University Medical Center.
It's our basic physiology at work, Allen tells WebMD. "Women's bodies are saving up fat to support growth of new life. It's genetically in our makeup. It's why we go to sweets."
Also, human females may be drawn to sweets for comfort or to reduce stress. Men are more satisfied with protein or fatty foods, says Allen. "And women under stress don't eat well-balanced, regular meals. They skip meals, eat meals on the run, don't get enough calories from nutritional foods to help them control hunger an hour or two or three later."
There's another factor at work: Overeating sweets promotes eating more sweets, Allen says.
Sweets make blood sugar go up, then dive back down, making you hungry again.
SOURCES: Eckel, L. American Journal of Physiology, November 2004. Lisa Eckel, PhD, Florida State University Program in Neuroscience. Darlene Allen, RD, Duke Diet and Fitness Center, Duke University Medical Center.
By Jeanie Lerche Davis
Reviewed by Michael W. Smith, MD
© 2004, WebMD Inc. All rights reserved