By:   Heidi McIndoo, MS, RD, LDN

While shopping today I counted no less than fifteen different types of oils with which to cook on my grocer's shelves. And if your store is anything like mine you have just as many, if not more.

Reasons for choosing one oil over another range from nutritional quality and cooking ability to flavor and price. Bottom line, everyone's needs are different, and there may not be just one that is the best for you.

In fact, right now I have five different kinds in my cupboard, and I use all of them regularly. So how should you decide which oils to use when you cook? First you need to understand their differences.

Nutritional Profile
Many of us choose how a cooking oil based on how it may affect our health--and for good reason. Cooking oil is one hundred percent fat, and we've all heard about how bad fat is for our hearts and waistline. Therefore, choosing the least harmful is certainly a good idea.

Surprisingly, most oils are similar in many ways, including calorie content. Oils differ mainly in the type of fat they contain, and this is where the "healthy" and "unhealthy" labels come into play.

There are four main types of fat that can be found in all food. These are probably terms you've heard of: Polyunsaturated, monounsaturated, saturated, and trans fats. What differentiates these fats is their chemical makeup. Most oils contain some sort of combination of these types of fats. So, what's what?

Monounsaturated fats are considered very healthy. They help to lower your total blood cholesterol level as well as your low-density lipoprotein (LDL), or "bad" cholesterol, while at the same time helping to raise your high-density lipoproteins (HDL), or "good" cholesterol, which decreases your risk of heart disease.

Polyunsaturated fats are also in the healthy category. These types of fats also lower both your total and bad cholesterol levels.

Healthy may seem like a funny word when applied to fat, but its true. Our bodies need some fat. "We can take in up to thirty-five percent of our calories from fat as long as we try to keep trans fats as low as possible and saturated fats to ten percent or less of total calories," according to Cynthia Sass, R.D., Spokesperson, American Dietetic Association. In addition to the healthy benefits mentioned above, fats are a good source of certain vitamins, including the antioxidant vitamin E.

Saturated fat was long considered the lone bad guy of the fat world. This unhealthy fat raises both your total and bad cholesterol, and in doing so, increases your risk of heart disease.

Trans fat is the latest nutritional villain. Not only does it raise your bad cholesterol levels, but it also lowers your good cholesterol levels. Fortunately, cooking oils don't contain any of these baddies.

Cooking Qualities
How you're going to use your oil can impact the oil you choose. Some oils are better at high temperatures than others. Cooking oils have what's called a smoke point. This is the temperature at which oil will begin to smoke. Butter and margarine smoke at around 302 degrees Fahrenheit. On the other hand, olive oil's smoke point is closer to 375 degrees Fahrenheit, and peanut oil's is 448 degrees, making these oils better for sautéing and frying, respectively. While deep frying isn't considered a healthy cooking method, if on occasion you choose to prepare food this way, having an oil that will heat to the necessary temperature (without smoking) is crucial. Deep frying in oil that isn't hot enough can result in more oil being absorbed into your food and, consequently, you consuming more fat.

Refined cooking oils are light and pale in both color and flavor. They are good for all types of cooking. Unrefined oils possess much stronger flavors as well as lower smoke points and are generally best for dressings, marinades, sauces, and other low temperature cooking.

Flavor
For cooking purposes, knowing how an oil tastes is critical. Some oils, such as canola, impart very little, if any, flavor of its own. However, sesame and truffle oils have quite strong flavors. You need to consider this when a recipe requires a half a cup of oil versus a drizzle.

Price
Price may or may not be important to you; however, it can often be useful to determine how an oil is best used. For example, an oil which costs only a few dollars for a large quantity is most likely meant to be used in large amounts. On the other hand, an oil that costs several dollars for a few ounces is probably meant to be used as a garnish.

Because prices are different all across the country, this guide will give you an idea of the price range for 8 ounces of a particular oil:

Here's a rundown of the key qualities of the most common cooking oils for you to refer to the next time you're choosing which one to buy.

Avocado oil

• $$$$
• A light buttery or nutty flavor, best for salad dressings or as a condiment and also cooking at very high temperatures
• Smoke point of 520 degrees Fahrenheit
• Composition is primarily monounsaturated fat—70%, with 10% polyunsaturated, and 20% saturated

Canola oil

• $
• Almost flavorless and therefore can be used in a variety of different recipes including sautéing, baking, and in salad dressings
• Smoke point for unrefined is 225 degrees Fahrenheit, semi-refined is 350 degrees Fahrenheit, and refined is 400 degrees Fahrenheit
• Composed of 62% monounsaturated fats, 32% polyunsaturated and 6% saturated

Corn oil

• $
• A tasteless oil that is most often used for frying, baking, and in salad dressings
• Smoke point of 320 degrees Fahrenheit for unrefined and 450 degrees Fahrenheit for refined
• Composed of 25% monounsaturated fats, 62% polyunsaturated and 13% saturated