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Nowadays, it seems like every food label is designed to make you think its contents are healthy (or at least not all that bad). And while a new Harris Interactive survey shows that the majority of Americans say they find those labels helpful in making healthy food choices, some of them mean diddly squat.

While the Food and Drug Administration is in charge of defining food labels, manufacturers are constantly coming up with new ones that aren’t regulated, don’t have any real definition, and are all about catching your eye. Meanwhile, the ones that the FDA has defined are rarely ever explained on food packaging—so the chances you know what they mean are slim says Nicolette Pace, founder of NutriSource in Great Neck, New York.

MORE: How to Get Nutrition Info for Recipes That Don't Come with It

So we tapped Pace—and the FDA’s food-labeling guide—to find out what the most common (and confusing) labels really mean:

1. “Made with…”

You think: It’s a good source of… whatever the ingredient the label is touting.

It means: It contains at least a bit of said ingredient. But since this label isn’t defined by the FDA, how much is anybody’s guess.

Shop smart: Get an idea how much of the ingredient the food contains by seeing where is sits on the ingredient list, says Lisa R. Young, adjunct professor of nutrition, food studies, and public health at New York University. The closer it is to the beginning of the list, the more of it the food contains.

2. “Natural”

You think: It’s not processed.

It means: It (probably) doesn’t contain added colors, artificial flavors, or synthetic substances. While the FDA hasn’t been able to agree on a definition for “natural” labels, it generally keeps an eye out for foods that contain those less-than-natural ingredients, Pace says. “It is hard to define a food product that is ‘natural’ because the food has probably been processed and is no longer truly ‘all natural.’”

Shop smart: See how long the ingredients list is. The fewer the ingredients, the less processed the food generally is, says Pace.

MORE: If Natural Foods Came with Ingredient Lists, This Is What They Would Look Like

3. “Lightly Sweetened”

You think: It has very little sugar.

It means: It could still have (what you might consider to be) tons of sugar or artificial sweeteners. The FDA does not regulate this label.

Shop smart: Look for any ingredients with an “–ose” ending—they’re a dead giveaway that the product contains sugars and sweeteners.

4. “Low,” “Light,” and “Reduced”

You think: It has few calories, grams of fat, grams of sodium, or whatever else the label lists.

It means: The product has less of that stuff than the original version. For instance, the FDA states that foods can be labeled “light” if they contain half the fat or one-third the calories of the original version, Pace says. Meanwhile, manufacturers are allowed to say products are “reduced sodium” if they have 25 percent less than the original or other similar foods. Keep in mind: When companies remove fat and salt from foods, they often replace it with sugar and additives to keep it yummy.

Shop smart: Before you buy, compare the “low,” “light,” or “reduced” nutritional label with that of the original to see how their pros and cons compare.

MORE: 4 Times It's Better to Go with the Full-Fat Version

5. "Free"

You think: It doesn't contain any of said ingredients.

It means: Apparently, in the food-labeling world, "free" means "very little." Specifically, 5 calories, 0.5 grams of fat, 5 milligrams of sodium, or 0.5 grams of sugar per serving, according to the FDA.

Shop smart: Again, a side-by-side comparison will serve you well. If you want to keep your supermarket trips quick, you can even look the nutrition labels up online before you hit the store.

6. "High in Fiber"

You think: It has a lot of natural fiber.

It means: For a food to be labeled high in fiber, it must provide 5 grams of fiber or more per serving. However, the fiber doesn't have to be natural. "It can absolutely can be an additive," says Young.

Shop smart: Look for whole grains on the label. If these are one of the first three sources, chances are the fiber's natural, she says.

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