Low calorie beverages come in many different varieties ranging from light beer to ordinary tap water. Some beverages are naturally low-calorie or calorie-free. In other cases, they are produced by replacing sugar with sugar-free sweeteners. A third category consists of beverages, such as light beer or skim milk, that have been modified to have fewer calories, but which are not calorie-free.
Water is the simplest of all low calorie beverages. Tap water in Western nations is almost universally safe for human consumption, and bottled or filtered water is available in areas where tap water may be unsafe or oddly flavored. Varieties of lightly flavored but unsweetened water are widely sold as well, and can be a good choice for people who dislike drinking plain water but are worried about weight gain.
Beverages based largely on water are also naturally low calorie beverages. Tea and coffee add flavor to water, but add no calories. Lime or lemon can also be added to water to add a bit of flavor without adding calories. Many cultures sweeten these water-based beverages — Thai iced coffee or sweet lemonade are definitely not low calorie beverages, for example.
A second variety of low calorie beverages are produced by replacing caloric sweeteners such as sugar or honey with sugar-free, non-caloric sweeteners. Soda, tea, coffee, and even some juice products are available with calorie-free sweeteners in place of sugar. Additionally, sugar-free sweeteners are widely available, and many people use them to sweeten their own beverages without adding calories.
Another category of low calorie beverages is produced by modifying existing beverages to reduce their calorie density. Skim milk is one example of this process. Whole milk is naturally high in both fat and sugars. Skim milk has had most of the milk fat removed, leaving behind only traces of fat and a fair bit of lactose, the sugar found in milk. It is not a calorie-free beverage, but it contains far fewer calories than whole milk and may be a good weight-loss beverage alternative.
Light beer is another example of a beverage that has been modified to have fewer calories. Alcohol is metabolized by the body to yield energy, and so it is impossible to produce a calorie-free alcoholic beverage. Light beer is a compromise of sorts, because enough grain products and alcohol must be left in the beer to provide its flavor and intoxicating effect, but the amount must be minimized to reduce the number of calories in the beer.