Sometimes, it's hard not to feel like the Big Bad Wolf at the gym: You huff and you puff, but you never seem to blow the weight away. And you probably never will. According to Jim Karas, author of The Petite Advantage Diet (HarperCollins), it's a myth that cardio leads to weight loss. But that's not the only fitness fallacy making the rounds. Here are a few key misconceptions.

• Cardio is good for weight loss
Not true, says Karas, who is also Hugh Jackman's personal trainer. "It does burn a few calories, but the operative word is a few. After twenty to thirty minutes of cardio, your body starts to chew up its precious muscle." Instead, he recommends interval training -- alternating fast and slow-paced cardio -- which is also less likely to leave you feeling famished.

• Weight lifting just bulks you up
In fact, strength training or lifting weights "is the key to weight loss because it is the only way to maintain and build lean muscle, which boosts your metabolism," Karas says. Science backs him up: A Tufts University study found that doing weights and resistance training can increase metabolism by up to 15 per cent.

• You can't get rid of a menopausal Buddha belly
Au contraire. Women of a certain age can combat the ravages of hormones by activating their transverse abdominal muscles, says Jennifer Hicks, a fitness trainer in Carleton Place, Ont. "You need to do functional core work, like a plank, rather than crunches. It's also a good idea to have five small meals of around 400 to 400 calorie-focusing on protein-which will level out blood sugar and kill the munchies."

• If you don't exercise, muscle turns to fat
"It's just not true," says Dr Rachel Vreeman, co-author with Dr. Aaron Carroll of Don't Cross Your Eyes...They'll Get Stuck That Way (St Martin's). "Fat cells and muscle cells are different things and one cannot convert into the other." But that doesn't mean you won't gain weight. If you do stop exercising, muscle cells become smaller and thinner, while fat cells enlarge as they store more fat.

Photography, Veer.