(MCT) -- Think of choosing food as choosing a new car. At one time, simplicity ruled. Most people would just find something familiar, salivate at the color, and buy.
Then terms like "hybrid" and "flex-fuel" and "continuously variable transmission" started buzzing around.
You had no clue what they meant, but they sounded important so you bought the car anyway.
Likewise, at one time a box of cereal was just cereal. It wasn't gluten-free, fat-free or cholesterol-free.
Now, for instance, Post Shredded Wheat boasts that it's "100 percent natural whole-grain wheat" and "helps reduce the risk of heart disease" and that "nine out of 10 doctors" recommend it. (The 10th perhaps is gluten-intolerant.)
What does this mean, and how much does it matter? Experts in the field of food say that varies.
"I think these things come in trends," says Abby Wood, a registered dietitian with Baylor Health Care System. "Dr. Oz puts out an article and - boom!"
The big underlying problem, says registered dietitian Eve Pearson of Nutriworks, "is that people try to cut something out. They look for the word 'free.' They look for something to be sugar-free or soy-free or dairy-free or gluten-free. That means a lot to people these days, and it makes me want to pull my hair out."
We asked for their help in sorting out which of the current buzzwords might actually matter.
What it means: The Food and Drug Administration guidelines state that a food must contain less than 20 parts per million of gluten in order to use "gluten-free" on its label.
Does it matter? Depends. Says Pearson: "It's just another thing to keep out of the diet and to follow something."
The trend, Wood says, "is huge."
So huge that last year, sales of these products were expected to reach $10.5 billion; by 2016, $15 billion. They target people who have an intolerance to gluten, a protein found in grains, as well as those suffering from celiac disease.
But only a very small segment of the population falls into this category. Meanwhile, Wood says, "everyone is self-diagnosing. It drives us dietitians crazy."
If the legitimate sufferers of disease eat gluten, they'll damage their intestines, she says. "But there's absolutely no benefit if you don't have it to avoid products with it."
Eliminating it can also come at a cost: missing out on important carbohydrates and fiber.
Pearson isn't surprised when clients tell her they feel better after going gluten-free.
"Overall, they've cleaned their diet," she says. "It's eliminated a whole lot of products like junk food and sweets and treats and snack foods."
But gluten itself has nothing to do with weight loss.
The takeaway: If you think you might be gluten-intolerant or have celiac disease, let your doctor make the diagnosis. If you're going to go gluten-free, Wood says, pick products that include whole quinoa flour, whole amaranth flour and brown rice flour - not potato starch or white-rice flour.
What it means: A product must contain less than 0.5 grams of fat per serving to bear this label, Wood says.
Does it matter? As pure as it may sound, fat-free is not a health panacea.
"A lot of times, manufacturers add more carbohydrates, and the fat-free products can be as caloric as regular" products, says Maria Jilma Bonaudo, a registered dietitian at Parkland Health & Hospital System.
Adds Pearson: "People look for 'free' but forget to see what's added to it instead to increase shelf life or flavor or a texture the consumer will keep buying. Fat-free salad dressing will have either a whole lot more salt and non-nutritive sweetener or a little more sugar. Low-fat peanut butter will have more sugar."
The takeaway: Opt for fat-free or low-fat in such products as milk, cottage cheese, chips, pudding, ice cream and microwave popcorn, Wood says.
What it means: This designation means the food contains the entire grain seed and has not been refined.
Does it matter? The FDA recommends eating at least three 1-ounce equivalents of whole grain - oatmeal, brown rice and whole-wheat products, for instance -a day.
Wood notes that whole grains are important, but that the numbers are confusing.
"A whole-grain serving is 16 grams," she says, "and a day's intake needs to be 48 grams."
Wood suggests looking at products that have the Whole Grain Council stamp. If it says "8g," that means the food contains at least a half-serving of whole grains.
The takeaway: Dietary guidelines say that half your grains should be whole grains, Pearson says. Check the ingredients list: If whole oat or whole wheat are one of the first listings, it's probably a good sign.
What it means: "This is a very unregulated term and can mean just about anything," Wood says. "People think natural peanut butter means it's organic or healthier. But it can contain as much sugar and fat."
Adds Bonaudo: "'Natural' can be a little misleading. 'One hundred percent natural juice' means it's made from fruit. But whenever things are processed, they may lose something" nutrition-wise.
The takeaway: Read the label. "A company can use natural to mean just about anything," Wood says. Some "natural" peanut-butter brands, for instance, may have added sugar and palm oil and pack more saturated fat then the regular version. "Be a label-reader, or buyer beware."
What it means: The FDA allows companies to use this designation for foods with fewer than 2 milligrams of cholesterol per serving and no more than 2 grams of saturated fat per serving. Saturated fats raise LDL (the so-called bad cholesterol) in your blood, and thus contribute to heart disease.
Does it matter? Manufacturers, Bonaudo says, "love putting 'no cholesterol' on cereal. It's a marketing staple to get you to buy a product."
Cholesterol is naturally found in animal products like organ meats, dairy, eggs and shellfish. Many products that say cholesterol-free wouldn't have had it anyway.
The takeaway: Again, don't let a product with the phrase "-free" sucker you into buying it.
What it means: Protein is an essential nutritional element. And Americans have decided they need more. So manufacturers are happy to add protein to products that used to be just as edible without it.
Does it matter: Lack of protein, Pearson says, "is definitely not an ongoing problem for Americans." But just because a processed food has protein does not mean it is nutritious.
The takeaway: Eat foods that naturally have protein, Pearson says. "There's no need to be buying foods that have added protein." Additionally, she says, spread intake throughout the day; don't wait till dinner to load up, because the body can only absorb and assimilate 30 grams of protein at a time.