It's a generally accepted belief that as you age, your resting metabolism slows --especially over age 40. And if you are a woman in menopause, your metabolism slows even more.

Not true, says a new paper published in Science. By analyzing data from nearly 6,500 people ranging in age from infancy to elderly, the paper's authors determined that resting metabolism holds steady from age 20 to 60 before logging a decrease of less than 1% per year thereafter.

Now you might be wondering why you feel like your metabolism has slowed down.

The answer is less about age and more about lifestyle. Although your baseline resting metabolic rate may not have changed between ages 20 and 60, the factors involved in boosting other aspects of your metabolism -- when you are not resting -- likely changed, lowering your ability to metabolize fat, maximize the caloric burn from exercise, increase energy-burning muscle mass and get quality rest to enable metabolic processes.