Natural, organic, free-range, hormone-free— suddenly food labels have nearly doubled in length. But while the organic food market is booming (with nearly $28 billion in U.S. organic sales in 2011, one study showed that 78 percent of families buy some organic foods), the buzzwords can confuse the average shopper. Study up on these terms before a trip to the store— the true definitions are surprising.

Organic: A USDA organic seal is the highest stamp of organic approval. Technically speaking, this label ensures that the product is made without synthetic fertilizers, sewage sludge (yes, really), irradiation, and genetic engineering. Any product with an “organic,” “100 percent organic,” or “made with organic [ingredient here]” label has to be certified by the USDA. For those products not entirely organic (less than 70 percent) the manufacturer must identify which ingredients are organic— but doesn’t get to boast the official seal of approval. The USDA standards also prohibit antibiotics and growth hormones in organic meats like poultry or beef, and require 100 percent organic feed for livestock. (Check out what foods are best to buy organic— some are a better deal than others!)

Cage-Free or Free-Range: The word pretty much sums it up on its own: Products stamped with “cage-free” or “free-range” means that the animals are given more freedom to move around… cage-free. “Cage-free” is used mostly for eggs, while “free-range” can include anything on Old McDonald’s farm (cows, chickens, and pigs alike). The tricky part? There’s no governmental certification to guarantee that the meat labeled this way is indeed from humanely-treated, free-roaming animals— and no restrictions mean that companies looking to cash in on the “organic” trend can make false “free-range” claims. Plus, some studies that there’s not much difference in nutrition between these “specialty eggs” and conventional ones— research suggests eggs from caged and cage-free animals contain similar amounts of bacteriaFatty acid composition and egg components of specialty eggs. Cherian, G., Holsonbake, T.B., Goeger, M.P. Department of Animal Sciences, Oregon State University, Corvallis, OR. Poultry Sciences, 2002 Jan;81 (1):30-3.Comparison of shell bacteria from unwashed and washed table eggs harvested from caged laying hens and cage-free floor-housed laying hens. Hannah, J.F., Wilson, J.L., Cox, N.A., et al. Department of Poultry Science, The University of Georgia, Athens, GA. Poultry Sciences, 2011 Jul;90 (7):1586-93..

Grass-Fed: While there’s no USDA stamp of approval for grass-fed animals, the best definition of a grass-fed animal is one who’s eaten nothing but mama’s milk, fresh grass, and hay. Look for products with an American Grassfed Association or Animal Welfare Approved stamp, which guarantee the animal was raised on a family-owned pasture or range. However, the jury is out on the possible related health benefits: Some studies show there’s no real health advantage of grass-fed beef, while others have found grass-fed beef to contain higher levels of healthy fatty acids and antioxidantsContamination rates and antimicrobial resistance in bacteria isolated from “grass-fed” labeled beef products. Zhang, J., Wall, S.K., Xu, L., et al. Department of Animal Sciences, Purdue University, West Lafayette, IN. Foodborne Pathogens and Disease, 2010 Nov;7 (11):1331-6.A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Daley, C.A., Abbot, A., Doyle, P.S., et al. College of Agriculture, California State University, Chico, CA. Nutrition Journal, 2010 Mar 10; 9:10..

Pesticide-Free: If a food product’s got the USDA Organic certification, it’s usually pesticide-free, too. Unfortunately, that’s not always a guarantee— studies have found that even some organic produce can contain pesticide residue. For truly pesticide-free food, look for a pesticide residue-free label.

Hormone-Free/Antibiotic-Free: The list of health concerns tied to hormone-filled meat is a doozy, from prenatal developmental problems to early puberty and infertility. Though the evidence isn’t always reliable, some studies have shown growth hormones from certain foods can disrupt hormones in humans and can even contribute to breast or prostate cancerThe concept of metabolic clearance rate in endocrinology. A case study of growth hormone in different lines of meat-type chickens. Herremans, M., Buyse, J., Decuypere, E., et al. K.U. Leuven, Faculty of Agriculture, Laboratory of Physiology and Immunology of Domestic Animals, Herverlee, Belgium. Hormone and Metabolic Research, 1993 Mar;25(3):142-8.. Again, a USDA Organic seal assures no hormones or antibiotics were used in the organic meat. But much like “free-range,” there’s no restriction about the term “hormone-free” or “antibiotic-free.” The best bet for hormone-free meat is to look for the USDA Organic label.

Natural or All-Natural: The term “natural” may be the most dubious of all— there’s no governmental regulation from the FDA or USDA for using the world on labels. “Natural” is a loose term for foods without synthetic preservatives, artificial sweeteners, and other additives. The only time the word “natural” is regulated is when it comes to meat, which requires the product have no preservatives and minimal processing. Again, food companies bank on the buzzword to bring in business— but they often over-exaggerate the claims. (Take the so-called “cereal giants,” who’ve been attacked for misleading the public with “all-natural” claims that don’t add up.)

Illustration by Elaine Liu