Women may have to work harder to lose weight, reports Shelby Sheehan-Bernard, of McClatchy-Tribune.
Face it: Losing weight is hard. And when you're a woman, the challenge seems even mightier. Maybe you've noticed how men seem to shed pounds with ease, while women are counting every calorie and still seeing fewer results. But is this battle of the sexes actually true?
Yes, according to Dr David Heber, director of the UCLA Centre for Human Nutrition. Because of a variety of factors - physiological, psychological and social - women have a tougher time staying fit.
• Physiological factors
A lot of it comes down to body composition, say the experts.
The difference is women in general tend to have less muscle mass and are smaller than men, according to Heber. This means that a man will burn more calories in both resting and workout states than his female counterpart.
Women also have a biological need to hold on to extra weight.
"In ancient times, women were pregnant and then would nurse for a year, even when food was scarce. Eating was very important for women to maintain themselves," says Heber, noting that the number of pregnancies a woman has increases her risk of weight gain.
Hormonal fluctuations related to a woman's monthly reproductive cycle can also make her susceptible to more food cravings than the opposite sex, according to Heber.
• Psychological and social factors
But we can't blame everything on the way our bodies differ.
"For a long time, I thought it was all about physiology," Heber says.
"Now I understand that there are cognitive behavioural issues happening."
In his programme at UCLA, where he says about 80% of his patients are women, Heber teams with a psychologist to help patients unwrap their emotional associations with food.
"We ask them: How do you feel about food? How do you use it as a stress reducer and what are the triggers?"
The social pressure to fit an ideal is stronger with women, making them more susceptible to quick fixes, Heber says.
"Women tend to be much more desperate about weight loss - the average middle-aged mum doesn't have any time for herself. So she looks up and has gained 25 pounds (11kg). Now she's looking for a magical food or programme rather than trying to educate herself about what's actually going on."
All of this, says Roberta Anding, a registered dietitian and spokeswoman for the American Dietetic Association, creates a perpetual cycle of disappointment.
"When you don't see results, you give in and eat emotionally, causing a binge of poor food choices."
• How to even the playing field
It's the ultimate maternal paradox that women are so able to take care of others and not themselves, a problem Heber sees often in his medical practice.
Alice Burron, a personal trainer and spokeswoman for the American Council on Exercise, is a mother of four children and understands first-hand how challenging it can be to make time for yourself. But she advises to schedule it like any other appointment and keep it.
Because the reasons for being overweight are complex, experts say that you may need a three-way approach of diet, exercise and counselling.
"If you're mired in guilt, you don't get anywhere," says Anding.
"Sometimes the person missing on the team is a psychologist."
Also be aware that weight isn't the best way to gauge your fitness level.
"A lot of women need to divorce from the scale and start dating body composition," says Anding.
This is especially true for older women who may experience bone loss or have less lean muscle mass - what Heber deems "skinny fat," where an individual may appear thin but actually has an excess amount of body fat. Check with your local fitness club or healthcare facility for body-composition testing.
As for burning the calories you eat, Anding has some simple advice: "Pound steel in the weight room."
She often has trouble convincing women of the power that strength training can have on women's ability to lose weight and tone up.
"Go to any gym and you'll see women on the elliptical paying so much attention to how many calories they're burning, but it's the strength training that will burn more," she says.
It can also help increase bone health, which is especially critical as women get older and become more prone to osteoporosis, according to Burron.
Anding also warns women against going light on the weights.
"The strength training has to be meaningful; you really need to go with the heaviest weight you can lift safely."
Burron suggests that women who need to build up strength begin with something simple, such as resistance bands.
Worried about looking like a bodybuilder? Don't be, say the experts.
"Most women couldn't bulk up if they tried," says Burron.
Whatever your goal is, keep it realistic and plan for gradual weight loss. And above all else, don't negotiate your health.
"Be kind to yourself," says Anding.
"But don't use chocolate cake as a reward."