The present invention provides flexible conventional polyurethane foams made from at least one polyisocyanate and at least one vegetable oil alkoxylated in the presence of a double metal cyanide (DMC) catalyst, optionally at least one non-vegetable oil-based polyol, generally in the presence of a blowing agent and optionally in the presence of a surfactant, pigment, flame retardant, catalyst or filler. The alkoxylated natural oil must have (a) an ethylene oxide content in the alkoxylated segment greater than 20% by weight, (b) a primary hydroxyl group content of at least 10%, with the sum of (a)+(b) being at least 30% but no greater than 60%, The alkoxylated natural oils are environmentally-friendly, bio-based polyols which can be used to increase the “green” content of polyurethane foams without having detrimental effects on foam properties.