Most foods are required to carry nutrition labels to provide, as the U.S. Food and Drug Administration (FDA) says, "distinctive, easy-to-read formats that enable consumers to more quickly find the information they need to make healthful food choices."

But despite being regulated by the FDA and the U.S. Department of Agriculture, food manufacturers can, and do, get away with adding confusing or deceptive information to the labels. Sometimes this is done inadvertently, but often it's done with the specific intention of making you think the food is better for you than it actually is.

Reading the labels can be tricky, so here are the six top nutrition label "catches" to watch out for on your next trip to the grocery store.

1. Serving Size. Many processed foods that are packaged as a single serving actually contain two or more servings. According to the Nutrition Labeling and Education Act (NLEA) of 1990, a food item in a relatively small container may be labeled as a single serving if the entire contents can "reasonably be expected to be consumed in a single-eating occasion." However, there is often a discrepancy.

Consider "Big Grab" potato chips or Doritos and "Big Gulp" drinks. Most people buy them with the intention of eating or drinking the whole thing. But an average serving of a soft drink is 12 ounces. Some of the Big Gulp drinks can be up to 64 ounces--more than five cans of soda! As for potato chips, a serving size can vary depending on the package. A single-serving snack size bag of chips, of course, has fewer calories than a larger, but still single-serving, size of the same snack.

Other items to watch out for include large muffins (which often contain two servings), bagels, "individual" ice cream containers (some contain 4 servings), and personal size pizzas.

2. Exempt Ingredients. Food labels list ingredients in descending order. The most prevalent ingredient is first, the least is last. However, ingredients that constitute less than 2 percent can be listed in any order after the heading "contains less than 2% of the following."

Other ingredients called "incidental additives" do not have to be listed on labels. These include substances transferred to food via packaging and "ingredients of other ingredients" that are present at "insignificant levels" and have no "technical or functional effect."

Natural and artificial flavors are also often grouped together under one name, and manufacturers aren't required to disclose what "artificial flavors" really means. The exception here is a new ruling by the FDA, to begin January 1, 2006, that states any food containing a "major food allergen" must have it listed on the label (whether or not its part of flavoring or incidental additives). Major food allergens include milk, eggs, peanuts, tree nuts, fish, shellfish, soy and wheat, as well as food ingredients containing proteins derived from any of these food categories.

3. All Natural. Food products that claim to be all natural may in fact include unnatural ingredients. According to Mike Adams, the "Health Ranger," "[The term all-natural] actually has no nutritional meaning whatsoever and isn't truly regulated by the FDA."

"The reality is that natural isn't always safe, and products with the 'natural' labeling are not required by law to contain only natural ingredients,'' said Linda Golodner, president of the National Consumers League. " ... Consumers think of words like 'safe' and 'good for me' when they think of natural, but across the board -- from prescription drugs to food products -- many of these natural claims are misleading at best.''

4. Free From ... The FDA allows food manufacturers to round to zero any ingredient that accounts for less than 0.5 grams per serving. So while a product may claim to be "gluten-free" or "alcohol-free," it can legally contain up to 0.5 grams per serving. While this may seem like an insignificant amount, over time this small fraction can add up.

Case in point, many food products that claim to have no dangerous trans fats list partially hydrogenated oil in their ingredients label. Partially hydrogenated oil creates trans fats, so these labels may be taking advantage of the rounding to zero option.

"If there's less than 0.5 gram of trans fats per serving, the food manufacturer may round down to zero," says D. Milton Stokes, R.D., a New York City-based nutritionist. "It's an FDA rule, and it happens with all foods."

5. Unfamiliar Terms for Unsavory Ingredients. Food manufacturers are known to use "clean labels," in which they hide ingredients they know consumers would rather not have in their foods under names they won't recognize.

For instance, if you're trying to avoid MSG, you need to look for all of the following terms, as they all contain MSG:

• Autolyzed yeast
• Calcium caseinate
• Gelatin
• Glutamate
• Glutamic acid
• Hydrolyzed protein
• Monopotassium glutamate
• Monosodium glutamate
• Sodium caseinate
• Textured protein
• Yeast extract
• Yeast food
• Yeast Nutrient

6. Misleading Ingredient Claims. Sometimes, foods that claim to include healthy ingredients actually don't contain them, or only contain them in miniscule amounts. Common offenders are blueberry waffles with no blueberries and strawberry yogurt with no strawberries. The Center for Science in the Public Interest (CSPI) recently asked the FDA to "immediately stop misleading food labels," including:

• Kellogg's Eggo Nutri-Grain Pancakes: The label says they're made with whole wheat and whole grain, but they're made primarily of white flour and contain more high-fructose corn syrup than whole wheat or whole grain.

• Betty Crocker Super Moist Carrot Cake Mix: Contains only carrot powder as the 19th ingredient on the label.

• Gerber Graduates for Toddlers Fruit Juice Snacks: The primary ingredients are corn syrup and sugar.

"Food manufacturers are shamelessly tricking consumers who are trying to eat more fruits, vegetables, and whole grains," said CSPI director of legal affairs Bruce Silverglade. "Too many processed foods contain only token amounts of the healthful ingredients highlighted on labels and are typically loaded with fats, refined sugars, refined flour, and salt, in various combinations."