When it comes to lifting weights, everyone has an opinion. One day you hear heaving heavy weights will leave you looking like a linebacker (it won't). The next day, rumor has it that supermodel limbs are a mere 10 minutes away thanks to the Miracle Machine du jour (not in this lifetime). The fact is, those little hand weights aren't the only dumbbells lurking around your gym. If all this conflicting information is enough to make you burn your jog bra and bag working out altogether, fear not: We sought out two of the most in-the-know pros in the fitness industry to clear up your confusion once and for all. 1. If you lift weights, you'll bulk up. "It's physiologically impossible," says Michael Wood, director of the Sports Performance Group in Cambridge, Mass., and an exercise physiologist at Tufts Research Center on Aging. The reason? Testosterone is responsible for a muscle's bulk, and women simply don't have enough of this predominantly male hormone to build Schwarzenegger-sized bulges. "Because muscle is denser than fat, strength training actually makes muscles shapelier," Wood says. 2. Weightlifting will get rid of saddlebags and any other unsightly bulges. If you buy that, rumor has it there's a Chiseled Cheekbones Through Self-Hypnosis franchise looking for investors. The sorry truth is that there is no such thing as "spot reduction." If you have a ripple here or a bulge there, your only recourse is to reduce fat all over. The best way is with a combination of cardiovascular exercise and strength training, says Norm Meltzer, a former competitive weightlifter. Here's why: Regular aerobic exercise burns calories and helps melt flab. Combine it with strength training (via free weights or weight machines), and you'll beef up your lean muscle mass, turning your body into a round-the-clock calorie-burning factory. (Experts estimate you need to take in an extra 50 to 60 calories per day just to maintain each pound of muscle you add to your frame.) "Area-specific exercises can improve appearance," Meltzer says, by tightening underlying muscles. "But it's wishful thinking that you can choose where to burn fat." 3. In order to see results, you need to work every muscle individually. Not only is it unnecessary to work each of your more than 600 muscles separately, you actually get a better workout (as in faster results in less time) by performing compound moves. Think squats, lunges, dips, push-ups. "Multijoint movements burn way more calories than single-joint exercises, so you get double the bang for your buck," says Wood. Another benefit: Unlike single-joint exercises (like a biceps curl or leg extension), compound moves mimic activities you're likely to perform in everyday life. This greatly reduces the chance you'll pull a muscle performing simple tasks like vacuuming or hauling groceries. 4. You need to eat a lot more protein if you lift weights. Your recent Perdue stock purchase aside, probably not. "The RDA protein requirement is .8 grams for each kilogram of body weight [1 kilogram equals 2.2 pounds]," says Wood. "With athletes, the number is only slightly higher, at around 1 gram per kilo." For a 130-pound woman, that translates into roughly 47 to 60 grams of protein a day. According to Wood, your liver and kidneys can only assimilate so much protein. Despite the pasta phobia that seems to be sweeping the nation, if you're underconsuming anything, it's probably healthy carbohydrates such as fruits, veggies, whole grains, rice, cereal, and juices -- all key nutrients for muscle building. "Carbs are our bodies' main source of fuel and should make up between 50 percent to 60 percent of your total caloric intake," Wood says. "Without adequate amounts, you may have difficulty sustaining a workout." 5. For maximum definition, the more repetitions of each exercise, the better. Au contraire, mes soeurs. "The only way you will ever see gains in strength, size, or power is by taking a muscle to momentary fatigue," Wood says. That means that you have to lift a challenging weight. "Once you can easily perform 12 repetitions of an exercise, increase the weight by 5 percent." Meltzer adds that as a part of a multidimensional approach to training, low-weight workouts aren't entirely without merit: "Repetition builds endurance, which is important -- especially if you participate in a sport," he says. In general, try to do at least two sets of each exercise and use a weight that's heavy enough so that you can barely lift it by the end of the second set. 6. If you stop working out, your muscles will turn to fat. Think apples and oranges: Fat and muscle are two different substances, and one cannot, will not, and has not ever turned into the other. Less of one simply means more room for the other. "When you stop using your muscles, your body becomes significantly less efficient at burning calories, which allows the pounds, in the form of fat, to creep back on," Wood says. If, say, a 150-pound woman stopped strength training, she may continue to see the same number when she steps on the scale, but her ratio of fat to muscle will shift dramatically. Women who work out with weights can slow the 10 percent loss of strength per decade that occurs in women who don't train with weights.