Cooking oils at too high of a temperature causes harmful fumes and the production of free radicals, which can damage your cells. You need oils with a high smoke point if you’re cooking at high temperatures. Oils sold as vegetable oil tend to be more highly refined, and as such have a higher smoke point than less refined oils, making them suitable for baking, frying, sauteing and marinating. Canola oil has a medium-high smoke point, so you can use it in similar ways to vegetable oil, but don’t turn the heat past medium. Corn and soybean oil have medium smoke points, and are better for sauces, low-heat baking and light sauteing due to their lower smoke points.