If you don't like the taste of still water but want to reap its health benefits, sparkling water is an acceptable alternative; it mimics the mouthfeel of soda without the adverse sugar overload. However, always check the label; some sparkling waters do contain sugar, which can contribute to weight gain, or other ingredients with their own potential health issues.
Although many sparkling water drinks are calorie free, some do have added sugar, sometimes in the form of fruit juice. Many people consume too much sugar, especially added sugar that is not naturally present in whole foods. Always read the nutritional labels of a beverage, and try to choose drinks that are low in added sugar. You can also make your own healthy, soda-style beverage by mixing plain sparkling water with a small amount of 100 percent fruit juice.
Some flavored sparkling waters are marketed as healthier alternatives to soda. While they may not contain sugar, some do contain artificial sweeteners such as aspartame, acesulfame K or sucralose. While artificial sweeteners have their critics, they're generally considered safe, although some do have known side effects; compounds called sugar alcohols can cause bloating or gas when consumed in large amounts. You should not consume more than the Food and Drug Administration's recommended maximum daily intake amounts of artificial sweeteners.
A 2007 study of sparkling-water beverages sold in the United Kingdom found that they may contribute to tooth erosion. The research, published in "International Journal of Paedriatric Dentistry," indicated a low pH and moderate acidity level in these drinks. While sugar is a large contributor to tooth decay, acidity plays a part as well. If you're concerned about tooth decay, avoid high-acidity drinks and ask your dentist for other recommendations.
Club soda and other sparkling-water products often contain a small amount of added sodium to enhance their flavor. A moderate amount of sodium is necessary to the human diet, but many people consume too much, which can lead to high blood pressure. You probably don't need to worry about the small amount of sodium in your drinks -- the biggest source is salt added to processed foods -- but switching to plain water would be one way to cut back on your sodium intake.