No one orders a beef-and-cheese-filled Gordita for a health kick. Still, when the ingredients list for Taco Bell's "taco meat filling" was recently exposed through a lawsuit, even fans of the Tex-Mex chain were shocked to learn how far outside the bun it was.

The ground beef used in Taco Bell products adds up to only about 36 percent meat, alleges the lawsuit recently filed against the company by a Florida woman. The rest of the meat filling, the lawsuit states, consists of things like isolated oat product, modified corn starch, caramel color, and the ever mysterious "natural flavors."

But should we be so surprised? As it turns out, food producers and sellers have access to all sorts of loopholes that allow them to present their products in ways that don't always feel entirely above board. Perhaps the most recent example came when Mike Adams, a natural foods advocate, reported that many of the “blueberries” found in cereal, granola, and muffins are more likely to be a combination of hydrogenated oils, flavors, and food coloring than actual fruit.

What seem like whole ingredients are sometimes instead combinations of processed and reconstituted additives, flavors, and ingredients. And thanks to modern food-processing techniques and clever marketing—or misleading labeling, depending on whom you ask—companies don't make it any easier. "It puts the consumer in a tough place,” says Michael Jacobson PhD., executive director of the Center for Science in the Public Interest. “It's unfortunate not being able to trust labels.”

If there is any blackberry or acai extract in Snapple's Acai Blackberry drink, it's such a trace amount that it's not even listed on the ingredients label.

Take Honey Nut Cheerios. While the breakfast cereal does contain some honey, the majority of the sweetness comes from sugar. Meanwhile, the ingredients panel doesn't list real nuts at all—just " natural almond flavoring," (The label warns that the product could contain almonds, but no almonds are on the ingredient list.)

It's illegal to practice deceptive advertising, but food companies have a lot of leeway when it comes to how they present their products. Some food ingredients must meet a "standard of identity" established by the Food and Drug Administration. If a food company says anywhere on its packaging that the product contains one of these ingredients, those ingredients must meet the necessary qualifications. But the list of products governed by these standards is limited—kept mostly to staples or foods that could be easily adulterated—and small compared with the number of products on the market. For instance, milk and chocolate must meet the FDA's standard of identity, but olive oil doesn't have to.

The FDA also has strict guidelines on how certain labeling and advertising terms should be used, but doesn't have the resources to check each individual claim. If consumers feel that a food is being misrepresented, they can request a review from the FDA, which will then issue a letter of warning should the company be found in violation of its policy, and in egregious cases, take the product off the shelves. According to Siobhan DeLancey, a spokesperson for the FDA, the administration took action on almost 150 claims last year.

But there's also a lot of gray area when it comes to how products are marketed. "There are real subtleties in this," says Jacobson, who notes that much of the law—including how much responsibility should fall to the consumer—is still being determined in the courts. "Should companies be allowed to put pictures of cherries on labels of cherry-flavored something or other, even if it contains no cherries? What if it's Jell-o? Does anyone really think there are real cherries in Jell-o?"

Cherries are a contentious topic when it comes to beverages, too, where cheaper bases like apple or pear juices are often the main ingredients in drinks marketed with more exotic flavors, like cherry or pomegranate. Snapple's Acai Blackberry drink, for instance, is mainly high fructose corn syrup and pear juice, with only a smattering of "natural flavor". If there is any blackberry or acai extract in the juice, it's such a trace amount that it's not even listed on the ingredients label. Meanwhile, drinks marketed as healthy or vitamin-enhanced are normally about as good for you as soda.

In fact, any product labeled "flavored" is worth a second look. Kantha Shelke, a food scientist and spokesperson for the Institute of Food Technologists, recalls that Kraft used to market "guacamole" that contained barely any avocado; a lawsuit ensued, and it's now sold as " guacamole-flavored."

Consumers should also be suspicious of added garnishes, like the aforementioned blueberries, and should check the food labels on the back of the packaging to ensure that the items advertised actually make the cut - and exist in recognizable form. “When you have a food label and see quite a lot of parenthesis—first tip that your food may be highly fabricated,” she says. “That tells me each one of these items were not as one would buy in a grocery store.”

Take the almonds in some ice creams. While almonds in a natural state have been shown to exhibit some appetite-suppressing properties, she says, some ice cream companies reconstitute them with a mixture of flour and modified starches to keep the nuts from getting soggy after months on the shelf. Those mixtures don't have the health benefits of whole almonds, and may actually increase your appetite. So if she wants something chunky in her ice cream, Shelke buys a plain flavor, microwaves it for ten seconds, then mixes in her own ingredients. "I have to do that because I want real nuts, and we have to at some point draw the line," she says.

But even sticking to basic ingredients can backfire. In 2009, The Wall Street Journal reported that a third of fresh chicken sold in the U.S. was injected with plumpers like salt water and seaweed extract. These additives still earned the birds a "natural" label, since both ingredients were naturally occurring—just not normally in chicken, says Jacobson. (In 2012, the USDA will adopt more extensive labeling laws for meat products, but it's unclear if the additives, which can drastically increase sodium content, will be revealed.)

But will it fix the Taco Bell problem? The company issued a statement after the lawsuit was filed, denying misleading advertising and vowing to fight the claims. The CSPI's Jacobson notes that very few meals served at restaurants—even fine dining establishments—would meet the criteria for pure ground beef, since most are mixed with some flavor, butter, and oil. Still, if you're concerned about nutritional transparency, maybe it's best to avoid fast food in the first place.