Do you enjoy a glass of wine with dinner or when unwinding at the end of a long day, but wonder how its calories are affecting your diet?

As with everything you eat and drink, it comes down to portion size.

The key is limiting yourself to one 5-ounce serving a day if you're a woman, two if you're a man. This is also the safe limit in terms of healthy alcohol consumption.

One serving of red wine has about 125 calories, with 100 calories for white. These calories can quickly add up if you refill your glass, yet they're hardly filling and have no nutritional value. So, it's important that you don't "spend" too much of your daily limit on booze.

To stretch a 5-ounce serving, switch to a smaller wine glass and pour just 2 or 3 ounces to start -- that leaves you some leeway for a refill.

Remember the tried-and-true trick of adding club soda or seltzer to wine to make a spritzer. Or mix in an equal amount of no-calorie lemonade and two orange slices for a simple sangria. And always sip rather than gulp.

If you like to cook with wine because of the flavor it imparts, keep in mind that the alcohol and its calories may not all burn off as many people think. How much is left depends on the cooking method you use and the amount of time the dish cooks for.

Bottom line: Sip carefully and wine won't be a diet buster.