Now your first reaction to this microorganism thing may be Eew bugs!  But the human intestinal tract has over 400 naturally occurring “friendly” bacteria.  These bacteria aid in digestion, stimulate the immune system, stave off the infiltration of pathogenic bacteria and virus’, and help with food and nutrient digestion.  Women on antibiotics are especially prone to yeast infections and one reason is that the antibiotic destroys the good bacteria in the gastrointestinal (GI) tract.  This is where yogurt can be most helpful as it adds back the friendly flora and normalizes the GI tract.   It also can aid in keeping the GI tract healthy even when not on antibiotics.  One of the bacteria often present, L acidophilus, has even been noted to contribute to the reduction of cholesterol by interfering with the re-absorption of cholesterol in the gut. 

There are many brands of yogurt on the market from highly sugared, high fat to the lightly sweetened lower fat variety.  Sugar free yogurt is usually low fat and uses aspartame as a sweeter.  There are also custard yogurts, whipped yogurts, fruit in yogurt, yogurt drinks, yogurt in a tube, frozen yogurt and candy or granola in the lid of yogurts.   Plain yogurt has a tart flavor and it often takes time for people to get used to this flavor but the calorie savings can be substantial.    Usually "sugar free" yogurt has the same amount of calories as plain yogurt.  You can even make your own yogurt.

Regardless of what type of yogurt you chose, to reap the desired health benefits it is essential that active live cultures are present in the yogurt.  It will say, “active live cultures” on the container.  In an attempt to ensure quality of product, The National Yogurt Association (NYA) has provided a seal for use only by companies that can ensure that 100 million cultures per gram are present at point of manufacture.  (Since this seal is strictly voluntary, there are yogurts without the seal that can still be rich in live cultures.)  If the yogurt has been heat treated, the live cultures have been killed.  Some Swiss style yogurts and many frozen yogurts are pasteurized after being produced thereby increasing the shelf life but eliminating the live active cultures.  Look on the container.

These same live cultures break down the milk sugar; thereby enabling lactose intolerant people to eat yogurt with no problem even though milk gives them cramps and abdominal bloating.  Since the calcium that milk and milk products provide is important for good health, this is an added plus.  Storage does reduce the amount of live cultures therefore yogurt is best when it is fresh, but the health advantages of calcium are always present.  

There is one word of caution.  Sugar is always empty calories even if it is added to a healthy food.  It is best to enjoy your yogurt with the least amount of sugar and additives as possible.