They say ignorance is bliss, so it's often easier to indulge in an unhealthy snack or meal when you don't know exactly how much exercise you would need to do to burn it off. Sure, some of you might say, "I don't care. I deserve to indulge." But we know that some of you would be horrified to know that you'd need to walk for more than five hours to burn off a Ruby Tuesday's Turkey burger, which weighs in at 1,173 calories. Or how about the ultimate indulgence for some people -- McDonald's fries? If you knew you'd have to walk for almost two hours to burn off 350 calories from a medium serving, would you still belly up to the drive-thru?

We challenge you to take this quiz from AOL Health. Test your knowledge of calorie counts in some of our favorite foods and see if they're worth the workout.

Fallen off the workout wagon because of a time crunch? Get back on track and save time with circuit training.

Liz Neporent is a diet and fitness expert and author of 12 fitness bestsellers. She regularly appears on national TV programs and is the president of Wellness 360, a New-York based wellness provider. You can also follow her on Twitter @lizzyfit.

Photo: Jervis_Pics, Flickr

Walking a mile burns the same number of calories as running a mile -- fit or fiction?

Well, this one is not so clear-cut. The answer is no, yes and it depends.

Walking at moderate speeds burns up to 40 percent fewer calories than jogging at moderate speeds over the same distance. This is because moderate walking is a more efficient way of moving and involves fewer muscles than running at a slow-to-moderate pace. When you walk, your legs are fairly straight as your foot strikes the ground. There is less impact, and your center of gravity remains relatively constant. All this conserves energy, e.g., burns fewer calories. Running is essentially jumping from foot to foot which is less energy efficient than the smooth glide of walking; because your knee is bent when your foot strikes the ground, muscles use up even more energy acting as shock absorbers and gravity fighters.

I love that blinking message on the cardio machine after my workout, 'Congratulations, you burned 350 calories.' But did you actually burn 350 or was it more like 300 or 450? I wonder if those calorie estimates are accurate. Especially since I've always suspected the elliptical estimates are bogus. From experience, these machines report that I've burned way more calories than my sweat or effort justify.

Turns out some cardio machines are more reliable than others, and my hunch about that elliptical may be right. Listen to what the experts have to say:

• Bicycle Calorie Estimates Are Fairly Believable -- assuming you're not Lance Armstrong, the variation in gym-goer mechanical cycling efficiency is fairly low, so converting watts into calories is an easy conversion.
• Stride Matters on a Treadmill -- a person's stride efficiency is more variable on a treadmill, so your true calorie burn can fall above or below the 'true value' used to determine the machine's calorie calculation. If your stride efficiency falls within five percent of the 'true value' estimate of 600 calories per hour, you'd fall somewhere between 570 to 630 calories per hour. But how do I compare my stride against 'true value'?
  
• Ellipticals Have No Standardized Equations -- says one senior product manager with Precor, so the accuracy of an elliptical equation depends on the amount of testing completed by the manufacturer. What kind of testing have they done to prove the validity of their machine's equation? Precor has thrown some money at a study analyzing the validity of its current equation, which measures calories via gas exchange measurements.

Considering caloric expenditure is generally a function of distance covered and body weight, make sure you enter in a correct body weight. Maybe we're splitting hairs on this whole calories-burned question, but no matter how accurate the machine is, I still adore that blinking 'congratulations.'

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