From this website - why men lose faster than women
Men tend to have more lean muscle tissue, which burns more calories than body fat, even during rest. And when men and women cut the same number of calories, men usually do lose more weight -- but it’s short-term. “Over the long-term, the playing field is more equal,” says dietician David Grotto, RDN, self-proclaimed “guyatician” and author of The Best Things You Can Eat. “It’s not a race to see who can lose weight the fastest. The important thing is that you’re both going in the same direction.”
Weight-loss programs often accentuate the difference. When sedentary men and women both start exercise programs, men tend to lose body fat, while many women don’t. In one study out of England, men and women were each put on commercial weight-loss programs such as Atkins, Slim-Fast and Weight Watchers. Two months in, the men had lost twice as much weight as the women -- and three times as much body fat. But by six months, the rate of weight loss had evened out between the genders.
If you’re a guy, you can thank the testosterone you have and the extra estrogen you don’t for your weight-loss edge. On average, women have between six and 11 percent more body fat than men, an assumed evolutionary adaptation to help during pregnancy. From puberty to menopause, women maintain more average body fat than men -- even when they take in fewer calories.
But it's important to remember that "fat" doesn't mean "unhealthy." Yes, women have larger fat stores, but it's part of their physiology, meaning it's not extra weight. So if a woman has 11 percent more body fat than a man, it doesn't mean she's 11 percent "fatter." A perfectly fit woman will still hold six to 11 percent more body fat than a perfectly fit man.
Also, men tend to lose weight where they need it most (read: belly), so it's often more immediately noticeable when overweight men start trimming down than when women do, as ladies' fat stores are typically more spread out, which is partly why they tend to lose weight at a slower pace than guys. Even basic, regular exercise ideally 30 to 60 minutes a day tends to reduce abdominal obesity, even if guys don’t technically lose weight.
Of course, ladies also lose abdominal weight quickly -- they just tend to have less of it. "Women with excess fat around the middle will lose it more or less as readily as men," says upwave review-board member David Katz, MD, MPH, the founding director of the Yale-Griffin Prevention Research Center at the Yale University School of Medicine. "Men are more prone to gain weight around the middle."
That said, carrying extra weight around the middle is also tied to increased heart risks, making it arguably unhealthier to be an overweight man than a plus-size woman. Big bellies, it turns out, are a sort of a double-edged sword when it comes to weight loss: They're an extra health risk for men, but give guys the edge when it comes to dropping pounds.
Ladies, don't despair: Women have weight-related advantages, too. They tend to carry more body fat on their thighs and backsides (the so-called “pear” shape), which are much healthier places to hold weight than around the middle. Plus, while women are better at storing fat, they also tend to burn more body fat during exercise than men do. "The fat women find it hardest to lose is generally the least harmful to health," Katz says.
At the end of the day, dropping pounds is hard work for women and men. And, really, it all boils down to this: Anyone can lose weight -- it doesn’t matter what your gender is. You just have to be committed to doing it.