During the '70s and '80s, fats and oils were considered universally bad. During the 1990s, research found that only some kinds of fats and oils were bad -- and that plant oils could actually help prevent the cardiovascular problems previously associated with all fats. This discovery led to a boom in the variety of plant oils available at the average American supermarket. Corn oil and sunflower oil are two such options.
The U.S. Department of Agriculture provides nutrition information for common foods. According to the USDA, corn and sunflower oil contain approximately the same number of calories: just over 1,900 per cup. In both cases, all of these calories are from fats. Note that cooking quantities for either oil are usually much smaller.
It's not the total fat in a food that matters, but the kind of fat. The fats in sunflower oil are about 90 percent healthy unsaturated fats and 10 percent unhealthy saturated fats. For corn oil, the split is about 85 percent unsaturated and 15 percent saturated. This makes sunflower oil a slightly better choice from a heart-health perspective. But in both cases the healthy fats overwhelmingly outweigh the unhealthy fats.
Two important characteristics in a cooking oil are flavor and smoke point, according to Food Channel personality Alton Brown. Corn oil has a lower smoke point -- the temperature at which it begins to burn -- than sunflower oil. This makes sunflower oil a better choice for high-temperature cooking such as deep-fat frying. Sunflower oil also has less flavor, so cooking in it is less likely to mask the attributes of the other ingredients.
The cost of any commodity, including cooking oil, fluctuates according to elements as diverse as weather, gas prices and trends. As of 2010, a review of products available at MySupermarket.com found prices for similar grades of corn and sunflower oil to match within 1 cent per milliliter of oil. But much like olive oils, there are more opportunities to spend extra on high-grade versions of sunflower oil.