Dietary phosphorus intake in the USA has been consistently greater than the Recommended Daily Allowance (RDA) with several studies reporting associations between intake and health risks as well as all-cause mortality within healthy subjects and patients with chronic kidney disease (CKD). The current study utilized a novel approach to calculate added phosphorus content in foods to determine sources (National Health and Nutrition Examination Survey, NHANES 2001–2016, n = 39,796) and trends in consumption (NHANES 1988–1994, 2001–2016, n = 55,744) of total, naturally occurring, and added phosphorus. Among adults (19+ years), the mean intake of total and natural phosphorus (mg/day) in 1988–1994 as compared with 2015–2016 increased (total: 1292 ± SE 11 vs. 1398 ± SE 17; natural: 1113 ± SE 10 vs. 1243 ± SE 16 mg/day); in contrast, added phosphorus intake decreased during this time (178 ± SE 2.9 vs. 155 ± SE 4.1 mg/day). Added phosphorus as a percent of total ranged from about 14.6% in 1988–1994 to about 11.6% in 2015–2016. The top five sources of total and naturally occurring phosphorus, representing approximately 20% of intake, were cheese, pizza, chicken (whole pieces), reduced-fat milk, and eggs/omelets. The top five sources of added phosphorus were cheese, soft drinks, cakes/pies, rolls/buns, and cookies/brownies, representing 45% of added phosphorus in the diet. Consumption of added phosphorus has decreased over the past few decades, possibly due to increased demand for foods with less additives/ingredients but may also be due to inaccurate phosphorus values in nutrition databases. Further studies are needed to validate the added phosphorus calculations utilized in this study and nutrition databases should consider providing added phosphorus content.