We all know that our nationwide weight epidemic has reached epic proportions. As a society, nearly two-thirds of Americans are overweight, and nearly one-third is obese. And while maintaining a healthy weight may seem to be quite a challenge, once you've made the decision to lose weight, knowing your own Body Mass Index measurement, and finding a target BMI to set your sights on, might be a great place to start.

In general, the Body Mass Index measures your weight in relation to your height. Once calculated, a BMI of 18.5 to 24.9 is considered healthy; a BMI of 25 to 29.9 is considered overweight; and a BMI of 30 or more is considered obese. (See sidebar on the right to calculate your own BMI measurement). By identifying your own BMI, you can not only evaluate where you're at, but also more accurately target a good weight loss goal for yourself.

Sure, it's true—we do live in a culture in which fast, convenient, and large are often the main descriptors of how and what we eat, but experts contend that weight gain is mainly the result of an "energy imbalance" over a long period of time.

Simply put, an energy imbalance is when the number of calories consumed by an individual outnumbers the number of calories used by him or her in a day; in other words, if you eat more than you burn, you're going to gain weight. Conversely, if you burn more than you consume, you'll lose weight.

Another way to look at it is like this:

One pound = 3500 calories

So to lose a pound, you must burn 3500 more calories more than you take in. Maintaining a healthy weight and BMI is all about balancing what you consume with what you burn—in essence, the relationship of diet to exercise.

Energy In, Energy Out

You can start working toward a healthy balance of diet to exercise today. One way to manage that balance is by thinking of the things you eat in reference to what it will take to burn them off. For example:

• One small cookie (50 calories) is equivalent to walking at a brisk pace for about 10 minutes. However, if you go for the larger, gourmet cookie you often see at the mall (200 more calories), you'd also need to rake leaves for about 40 minutes to burn off that one "treat."
• If you decide to go for that jelly doughnut sitting in the office break room (300 calories), then get set to walk about one hour at a moderate pace to wear it off.
• Thinking of ordering the fast food "value" meal at lunchtime? If you choose the double cheeseburger, extra-large fries and 24 oz. soft drink (and note, these are not even the "biggie" sizes), you'll be taking in about 1500 calories, and would need to run for about 2 ½ hours at a strong pace to burn off just that one meal.
• Want to lose 10 pounds by this time next year? If you don't change anything else about your diet except simply cutting out one, 12 oz. can of regular soda (150 calories) 5 days each week, in 52 weeks, you will have decreased your caloric intake enough to lose 10 pounds.
• Want to wear off another 150 calories each day? Try doing these activities:
  • Washing your car for 1 hour
  • Gardening for 45 minutes
  • Pushing a stroller 1.5 miles in 30 minutes
  • Walking 2 miles in 30 minutes
  • Raking leaves for 30 minutes
  • Playing volleyball for 45 minutes
  • Shooting baskets for 30 minutes
  • Bicycling 5 miles in 30 minutes
  • Doing water aerobics for 30 minutes
  • Jumping rope for 15 minutes
  • Running 1.5 miles in 15 minutes

The opportunities to balance your diet with exercise—to regulate the calories you take in and the calories you burn each day—are endless. With a little forethought and some elementary math skills, you can easily identify ways to lose weight, or to maintain a balance once you've reached a healthy weight. And through that balance, you can maintain not only a healthy BMI, but also a healthy lifestyle for years to come.