Unsaturated polyester compositions are disclosed that are obtainable by reacting: (i) plant and animal oil triglycerides, an alkyl ester of a saturated or unsaturated fatty acid or mixtures thereof; (ii) a difunctional, or polyfunctional glycol or mixtures thereof; (iii) a difunctional or polyfunctional acid, their anhydrides or alkyl esters and mixtures thereof; (iv) a strained cycloolefin; (v) a component(s) that function as a compound capable of initiating polymerization at high temperature and which is stable at room temperature; and (vi) low profile additives, fillers, and reinforcements. Also disclosed are methods for the preparation of the polyesters and the use of the polyesters in closed and open mold compositions such as sheet molding compound (SMC), bulk molding compounding (BMC), resin transfer molding (RTM), pultrusion, infusion, filament winding, and spray up.