Fact

You hear a lot about working out in the morning. And while it's a great way to ensure you get your time in before the day gets away from you, it won't kickstart your metabolism the way some say. Several studies have found that you burn more fat and build more muscle in the evening. Researchers at the University of South Carolina found that we are at our fastest and strongest between 7 pm and 11 pm, thanks to our circadian rhythms. Our weakest time? 7 am.

Fact

If you focus solely on cardio exercises and ignore strength training, your body will actually get rid of muscle mass and it will be hard to lose fat at all. The American College of Sports Medicine recommends a combination of cardio and strength training. More muscle helps your metabolism stay high. And while weight training doesn't burn a ton of calories, the more lean mass you carry, the higher your all-day energy expenditure will be. Muscles require fuel all the time, so you'll be burning calories more efficiently even when you're not working out.

Fact

No doubt that crunches engage and strengthen your abdominal muscles, but you'll never see them if there's a layer of fat over them. If you want toned abs, experts agree that you need to limit your carbohydrate intake, get plenty of sleep and minimize stress. With that foundation in place, you can use interval training to burn stored fat and let your inner washboard shine though.

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You might've heard that when you stop weight training, that unused muscle turns to fat. But that's impossible. When you take a break from lifting weights, you lose some muscle mass, which in turn slows your metabolism. A slower metabolism can cause weight gain, but one type of tissue cannot turn into the other. Furthermore, a study published in Archives of Physical Medicine and Rehabilitation, found that for athletes, “strength performance in general is maintained for up to four weeks of inactivity.” So a week off isn't derailing any progress.

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If you're looking to maintain your strength and health, then a high-intensity interval training program like this one published in the ACSM's Health & Fitness Journal might do the trick. But losing weight is still a numbers game. Shorter high-intensity workouts can spark your metabolism, but that's merely a drop in the bucket in terms of overall calorie burn. The more calories you melt, the more weight you lose.

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“This is just wishful thinking,” says Shirley Archer, a fitness and wellness educator with the American Council on Exercise. Fat reduction—in the midsection and elsewhere—will happen with a combination of healthy eating, cardio and strength work, she says. Unfortunately, you don't get to pick one body part or another.

Fact

Sports drink commercials do a good job to sell this idea, but the truth is that plain old water will easily get you through a workout. Electrolyte-pumped sports drinks are really only necessary for gym sessions or intense cardio workouts that last an hour or more. And keep in mind, the extra sugar in sports drinks can set back the fat-burning process.