I'm one of those people who lives to eat. Luckily, I've been able to keep any unwanted extra pounds at bay thanks, in part, to my passion for running and also, in part, to my commitment to eating as many fruits and vegetables a day as possible.

My love of food (it's an obsession, actually, according to this quiz: Are you obsessed with food?) is so great that for years I've been dreading the day my metabolism hits the brakes and slows down. Metabolism slows by 1 to 2 percent each decade after age 30, and that's just around the corner for me.

But a slower metabolism is most marked in one's sixties and beyond. Why? There's a significant decrease in muscle in your sixties, particularly in women. And since muscle is a calorie-burning powerhouse, muscle loss equals fewer calories burned.

So while the aging-metabolism situation isn't as imminent as I'd assumed, I'm determined to age gracefully (I love these 7 Foods to Keep You Young) and outsmart any weight gain by preserving muscle mass with strengthening exercises. Regular exercise can help offset reduced muscle metabolism and help you stay lean.

And, of course, I plan to eat a diet a bit lower in calories. That said, it's hard to know just how many calories you should be eating each day to maintain, or lose, weight. I like to use EatingWell's calorie calculator-it's a quick and easy way to calculate your calorie goal.

Overall, remember that the key to managing an aging metabolism is to maintain a healthy weight (check out these 8 Tips to Shape Up Now) and exercise regularly, making sure to include some strengthening exercises.