Getting a little culture.

It helps prevent cancer. It lowers cholesterol. It fights infections. It aids digestion. Eat it and you'll live to 100.

Not bad for fermented milk.

Yogurt might do all that. . . or it might not. You'll have to wait for our upcoming article to find out.

In the meantime, just look for a yogurt that's not loaded with sugar and fat.

A MOOVING TARGET

Odds are your yogurt is at least as fatty as the milk from which it's made.

That means an eight-ounce tub could have no fat (if it's made from skim milk) . . . or as much as nine grams of fat (if it's made from whole milk). Make that 12 grams for Alta Dena plain Whole Milk Yogurt, which adds insult (cream) to injury (whole milk).

Still, finding a healthy yogurt is a snap. For our "Best Bites," we looked for yogurts that got no more than 15 percent of their calories from fat. We found more than 200.

If you don't want to calculate calories from fat, don't worry. Just buy a non-fat yogurt. Your best bet is to buy it plain (or make it yourself) and mix it with some berries or other fresh fruit.

SWEET AND SOUR 

The problem with most yogurts isn't their fat. It's their added sugar, corn sweetener, or fruit-juice concentrate.

Companies aren't yet required to disclose how sugary their yogurts are. And, guess what? Many don't.

Dannon did tell us that an eight-ounce cup of its Classic Flavors like Coffee or Vanilia contains about four teaspoons' worth of sugar. Ditto for a six-ounce cup of its Blended yogurts. An eight-ounce cup of its Fruit-on-the-Bottom has six teaspoons.

There's no reason to think that other manufacturers use less. In fact, Hughes Lowfat Fruit on the Bottom or Pre-Stirred contains nine teaspoons of sugar.

(Ounce for ounce, fruit-blended and fruit-on-the-bottom yogurts generally have about the same amount of sugar. It's just that the blended's fruit is already mixed in when you buy it. Flavored yogurt typically has about a third less sugar than the other two.)

And sugar means calories. While eight ounces of plain non-fat yogurt averages 90 to 110 calories, fruited yogurts can go as high as 250 calories (Breyers Lowfat or Lucerne Pre-stirred Lowfat, for example).

A handful of companies keep the calories to 100 or less by using the artificial sweetener aspartame. We'd stay away from them, since aspartame hasn't been adequately tested.

CALCIUM BY THE SPOON

Since yogurt's made from milk, an eight-ounce serving of most yogurts will give you at least 30 percent of the U.S. Recommended Daily Allowance (USRDA) for calcium.

For some brands, it's 40 percent or more. Chalk it up to their added non-fat milk solids, which are rich in calcium.

Naturally, you'll find less calcium (around 25 percent of the USRDA) in yogurts that come in six-ounce cups. And you'll find next to none in non-dairy soy yogurts.

Six ounces of Soya Latte, for example, contain just three percent of the USRDA, while White Wave Dairyless clocks in at four percent. Too bad soy yogurt manufacturers don't add calcium.

The calcium in yogurt is made to order for people who have difficulty digesting milk sugar (lactose). The beneficial bacteria in the yogurt do most of the digesting for them. Which means a nice dose of calcium. . . without a far-less-nice dose of stomach discomfort.

THE CULTURAL REVOLUTION

If yogurt does have curative properties, they're probably due to its live cultures.

Yogurt is made by adding two types of bacteria-Lactobacillus bulgaricus and Streptococcus thermophilus - to warm milk. The bacteria convert the milk's sugar (lactose) to lactic acid, which gives yogurt its sour taste.

Do they also keep your colon healthy.? Or prevent vaginal yeast infections? Or replace the beneficial bacteria that are killed when you take antibiotics? We're looking into it.

One thing they do do is sell yogurt.

But you needn't bother looking for them, or for the National Yogurt Association's new "Live & Active Cultures" seal.

According to Dennis Saviano, a researcher at the University of Minnesota who has analyzed brand-name yogurts, "commercial refrigerator yogurts all contain about the same range of bacteria." (That's not the case with frozen yogurts, many of which have few active cultures.)

Recently, Dannon and a few other companies have begun to add one or two additional cultures to their yogurt. That's because, unlike the regular bacteria, Lactobacillus acidophilus and Bifidobacteria aren't killed before they reach the large intestines. That means they could be even more beneficial.

If you're hunting for active cultures, keep in mind that whatever space in the tub is taken up by sugar or fruit isn't taken up by yogurt . . . or yogurt bacteria. Which is yet another reason to add your own fruit to plain non-fat yogurt.

YO, GERT 

"Best Bites" get no more than 15 percent of their calories from fat and contain at least 30 percent of the U.S. Recommended Daily Allowance (USRDA) for calcium. They also have no added candy toppings. (We didn't use sugar as a criteria because we couldn't squeeze the numbers out of most manufacturers.)

"Honorable Mentions" would be "Best Bites" if they weren't packaged in smaller containers. (Who needs' em? They just add expense and tough-to-recycle garbage.) Ounce for ounce, they still had to meet the "Best's" fat and calcium requirements.

"Worst Bites" get more than 40 percent of their calories from fat. Products are ranked from lowest to highest percent of calories from fat.