"Processed foods" are defined as any foods other than raw agricultural commodities and can be categorized by the extent of changes occurring in foods as a result of processing.
A study published in The American Journal of Clinical Nutrition shows that the majority of calories consumed by U.S. households may come from processed foods.The researchers set out to determine trends in the contribution of processed and convenience food categories to purchases by U.S. households, and to compare saturated fat, sugar, and sodium content of purchases across levels of processing and convenience. To do this, they analyzed purchases of consumer packaged goods for 157,142 households from the 2000–2012 Homescan Panel. They explicitly defined categories for classifying products by degree of industrial processing and separately by convenience of preparation. They classified more than 1.2 million products through use of barcode-specific descriptions and ingredient lists.
The researchers found that more than three-fourths of energy in purchases by U.S. households came from moderately (15.9%) and highly processed (61.0%) foods and beverages in 2012 (939 kcal/day per capita). Trends between 2000 and 2012 were stable. When classifying foods by convenience, ready-to-eat (68.1%) and ready-to-heat (15.2%) products supplied the majority of energy in purchases. In addition, they found that 60.4% of the highly processed foods were found to contain more than 10% kcal from saturated fat, 15% kcal from sugar, and 2,400 mg sodium/1000 kcal, whereas only 5.6% of less-processed foods and 4.9% of foods requiring cooking/preparation fell into this category.
The researchers concluded that "highly-processed food purchases are a dominant, unshifting part of U.S. purchasing patterns yet may have higher saturated fat, sugar, and sodium content compared with less-processed foods. Wide variation in nutrient content suggests food choices within categories may be important