It's really not that hard. We have to look at the ingredients. If an ingredient has been chemically altered then that is a "processed" food IMO. The easiest thing for consumers is if you can't pronounce the ingredients, or don't know what they are, don't buy it.
[forgive capitals, I'm copying this from their websites]
Amy's Macaroni and Cheese: ORGANIC MACARONI (ORGANIC UNBLEACHED DURUM WHEAT FLOUR, ORGANIC WHOLE DURUM WHEAT FLOUR, FILTERED WATER), ORGANIC LOWFAT MILK, WHITE CHEDDAR CHEESE (PASTEURIZED MILK, CULTURE, SALT, ENZYMES [WITHOUT ANIMAL ENZYMES OR RENNET]), BUTTER (CREAM, SALT), ORGANIC SWEET RICE FLOUR, SEA SALT, ORGANIC ANNATTO (COLOR). CONTAINS WHEAT AND MILK.
Kraft Mac and Cheese: PASTA (ENRICHED WHEAT FLOUR [WHEAT FLOUR, NIACIN, IRON (FERROUS SULFATE), THIAMIN MONONITRATE, RIBOFLAVIN, FOLIC ACID], WHOLE WHEAT FLOUR, GLYCEROL MONOSTEARATE), CHEESE SAUCE MIX (WHEY, CORN SYRUP SOLIDS, MILK, MILKFAT, PALM OIL, MODIFIED FOOD STARCH, SALT, MILK PROTEIN CONCENTRATE, MALTODEXTRIN, CONTAINS LESS THAN 2% OF CALCIUM CARBONATE, SODIUM TRIPHOSPHATE, MEDIUM CHAIN TRIGLYCERIDES, DRIED BUTTERMILK, CITRIC ACID, SODIUM PHOSPHATE, LACTIC ACID, CALCIUM PHOSPHATE, NONFAT DRY MILK, GUAR GUM, CHEESE CULTURE, WITH PAPRIKA, TURMERIC, AND ANNATTO ADDED FOR COLOR, SILICON DIOXIDE, ENZYMES, NATURAL FLAVOR, XANTHAN GUM), MODIFIED FOOD STARCH, MALTODEXTRIN, ACETYLATED MONOGLYCERIDES, SALT, MEDIUM CHAIN TRIGLYCERIDES.