We gleefully cheers to the fact that one glass of red wine a day is good for our health [1], but how much, exactly, is a glass? The answer depends on who's pouring, and the differences in those few ounces can make all the difference.

While a normal serving of wine is five ounces (and 127 calories per glass of red [2]), a recent study found that the size, shape, and location of your wineglass influences how much you pour. The study participants poured 12 percent more [3] when using a wide glass than when using a standard one, for example, as well as when they held the glass instead of placing it on a table. If you have a glass of wine every night, then that 12 percent can really add up. Those extralarge glasses just mean more empty calories, and drinking more than one glass a night can lead to weakened bones and an increased risk of certain diseases [4]. The detrimental effects of a daily "large" glass of wine on complexion was even chronicled by a Daily Mail article [5] in 2013.

The good news is that the wine-pour study found that participants tended to overpour white wine rather than red (since the color contrast of the wine and the clear glass isn't as apparent), so if you are sticking to red for its health benefits, then you may not be overpouring as much as researchers think. Either way, this study is a great reminder to be conscious of when you imbibe; these tips can help you pour correctly.

• Use a narrow wineglass rather than a wider tumbler or glass when you drink wine.
• Always pour with your wineglass on the table, not in your hand.
• When pouring in traditional red-wine glasses (which are larger than white-wine glasses), stop once the wine reaches the "bell," or the widest part of the glass. Usually this will be around four or five ounces.
• If you like to enjoy a glass of wine every night, then make sure the bottle of wine lasts you five nights; there are about five glasses of five-ounce pours in every 750 mL bottle of wine.