Arby's own August 2026 ingredient guide lists the fryer oil as corn, soybean, canola and hydrogenated soybean oil with dimethylpolysiloxane, and 67 of its 70 food components carry an additive. The roast beef itself is just beef, water, salt and phosphates - it is the bun and the sauce that get you.
Arby's publishes a full Menu Items and Ingredients guide dated August 2026, and it is a more complete disclosure than most - it maps every sandwich to its components and then gives a statement for each one. The fryer oil is listed outright as Corn Oil, Soybean Oil, Canola Oil and Hydrogenated Soybean Oil with dimethylpolysiloxane, and every bun and roll lists soybean or cottonseed oil, so a Classic Roast Beef still has a seed oil in it even though the roast beef itself is only beef, water, salt and sodium phosphates. Of the 70 non-drink components, 42 list a named seed oil and 67 carry an additive - the only three clean of additives are Ketchup, the natural Swiss slice and Tree Top applesauce. The chicken carries MSG twice, once in the marinade and once in the breading.