The math is pretty simple. One pound of fat equals 3500 calories. Want to lose a pound a week? Then you need to consume 3500 calories less per week than you use. That's about 500 calories a day.

By cutting out 500 calories a day from your normal daily diet, while keeping your activity level the same, you can lose approximately one pound a week.

All right - that doesn't sound like much, especially if you're more than 25 pounds overweight. Study after study has shown, though, that those people who lose weight gradually - at a rate of 1-2 pounds per week -are far more likely to keep the weight off and maintain a normal weight for a lifetime. 

So how much exactly IS 500 calories? If you're going to reduce your daily intake by 500 calories, it helps to know what you need to cut out, right?

Here's how easy it is to lose 500 calories a day: 

* Use milk instead of cream in your coffee. Savings? 50 calories per cup. 

* Skip the butter on your baked potato. Savings? 100 calories 

* Drink fruit-flavored water instead of a 16 ounce soda. Savings? 200 calories 

* Skip the Big Mac and have a salad instead. A Big Mac weighs in at a whopping 460 calories. A fresh salad with a light dressing? Less than 100! Savings? 360 calories 

* Pass by the bag of potato chips. An average snack size bag of chips has over 300 calories. Savings? 300 calories 

* Eat your corn on the ear. A 1 cup serving of canned corn has 165 calories. An ear of corn has 85. Savings? 80 calories. 

* Switch to low-fat cream cheese on your bagel. Savings? 90 calories per ounce. 

* Love those fries and can't give them up? Swap the skinny fries out for thick steak-cut ones. Thin French fries absorb more oil than the thicker, meatier ones. Savings? 50 calories per 4 ounce serving 

If you'd rather look at losing weight from an exercise perspective, you can also lose one pound a week by upping your activity level by 500 calories a day. How easy is that to do? Take a look: 

* Take a half-hour walk around the park. Aim for a pace that's a little faster than a stroll, but not fast enough to be breathless. Burn: 160 calories.

* Get out your bike and take a ride. Tackle a few moderate hills and aim for about five miles total. Burn: 250 calories

* Go dancing - and really DANCE. The longer you're out on the floor instead of at the table drinking up high-calorie drinks, the more you'll get out of it. Dancing that makes you breathless and warms up your body will net you a nice calorie savings. Burn: 400 calories for one hour 

* Swimming is great for you, and a lot of fun, too. The water resistance means you burn more calories, and you avoid the stress impact on joints from aerobics, dancing or walking. Do a few laps at a slow crawl - if you can get up to an hour you'll be doing great! Burn: 510 calories 

* Get out into your garden. An hour of gardening tasks that includes bending and stretching can burn up to as many calories as a brisk walk. Burn: 250 calories. 

* Play a game of tennis. Hook up with a friend for a weekly tennis game and you'll be amazed at the difference. One hour of vigorous tennis is one of the best calorie burners around. Burn: 800 calories 

It’s important to keep in mind that all exercise/calorie numbers are based on a woman weighing 130 pounds. If you weigh more, you'll burn more. Want an added bonus to burning calories through exercise? When you exercise, you build muscle by converting it from fat. Three guesses which kind of body tissue burns more calories - even when you're not exercising. You got it - your body uses more energy to maintain and feed muscle than it does fat. 

For best results, mix and match food savings with exercises that burn calories. Do keep in mind that eating less than 1000 calories a day for more than a few days will convince your body that it's starving and slow your metabolism. Keep calorie ranges reasonable, and consult a doctor if you want a quicker, more drastic weight loss.