Although women burn off more fat than men during exercise, they don’t lose as much body fat with exercise. That’s because women store fat more efficiently then men, despite eating proportionally fewer calories. But why?
New research from the University of New South Walessuggests a link between estrogen and its impact on fat storage for childbearing.
According to the studies, the female sex hormones estrogen reduces a woman’s ability to burn energy after eating, which results in more fat being stored around the body.
On average, women store 6 to 11 percent more body fat than men.
“Female puberty and early pregnancy–times of increased estrogen–could be seen as states of efficient fat storage in preparation for fertility, fetal development and lactation,” study author Anthony O’Sullivan explained.
A pesky hormone
Meanwhile, in his post 3 Foods Vegetarians Must NOT Eat for Fat Loss, fitness trainer Craig Ballantyne warns against consuming excessive amounts of soy, which has an estrogenic effect in the body.
“Most vegetarians consume copious amounts of soy. Heck, it is not uncommon to see soy milk for breakfast, soy burgers for lunch and soy ice cream for a late night snack,” Ballantyne writes in the post, which is aimed at vegetarians trying to lose body fat.
“These foods can stop your fat loss dead in its tracks. In addition to all of the sugar and salt these products contain, soy has an estrogenic effect in the body,” he warns. “Excess estrogen binds to the fat cells and causes an increase in the size of estrogen-sensitive fatty tissue such as belly fat.”
Weight gain and birth control
And now, a recent University of Texas Medical Branch study found that women using the birth control shot depot medroxyprogesterone acetate (DMPA) gained an average of 11 pounds and increased their body fat by 3.4 percent over three years.
“One concern is DMPA’s link to increased abdominal fat, a known component of metabolic syndrome, which increases the risk of cardiovascular disease, stroke and diabetes,” lead author Abbey Berenson said.
Berenson, however, notes that the mechanism by which DMPA causes an increase in weight gain and fat mass is not known. No link was found between DMPA use and caloric intake, fat consumption or amount of exercise on body mass changes.
The women who switched from DMPA to oral contraception gained an average of four additional pounds in the same time span while those who switched to non-hormonal contraception slowly lost the weight and fat mass they had gained.
Berenson suggests women and their doctors should factor in this new data when choosing birth control methods.
Why does this matter to you? Because while estrogen promotes body fat storage (testosterone, by contrast, promotes lean body mass), exercise and a healthy diet can turn the ill effect around. And women taking hormonal contraception were also less likely to lose muscle mass and gain body fat when they exercised regularly and consumed a healthy diet that included increased protein intake.