There are a number of people who claim cooking with olive oil is something you should not do; others simply claim that as long as you know the quality of the oil (virgin, extra virgin, etc), and how to properly work with it, there should be no issues. The later is the case, and as long as you know how to work with the oil, you will find it is not only a healthier alternative for many dishes you would otherwise use fat or canola oil for, but it is also a tasty option when you use it properly in the dishes.
This is the most important factor to consider when cooking with olive oil. Olive oil has a much lower smoke point than canola, coconut oils, and lards. This means if it reaches this point, it will release free radicals and harmful carcinogens. The thing many people don't know is that it is very difficult to truly reach the smoke point. So, as long as you are aware of it, and know what temperatures you are working with, this should not be an issue when you are cooking with this type of oil.
Another important and relevant factor to consider is the quality of the oil. Spanish and Mediterranean oils tend to be purer. Further, an extra virgin olive oil will have a higher smoke point than virgin or plain olive oil. These discrepancies will make a great deal of difference when using the oil for certain dishes, especially if you need to cook a dish at a higher temperature setting, extra virgin olive oil will be your best bet.
When it comes to fatty dishes, such as French fries, frying chicken, or other similar dishes, avoid using olive oil. Instead, you should use lard or oils which have the highest smoke points. Although olive oil would make it a healthier dish, it won't properly cook these foods, and it will release harmful radicals when cooking. So, go with dishes that are closer to a simmer, or lower heat levels.
When cooking with olive oil, also remember to raise the temperature gradually for any dish you are making. If you heat the oil at the highest heat, it will burn. If you increase the temperature too quickly it will burn. Rather, start at a low heat and place the oil in the pan; from there, increasing it gradually will result in the purest taste, and will of course avoid burning the oil and your dishes.
You also want to avoid going past 375 degrees F. This is close to the smoke point, meaning it is sure to burn any dish. When cooking with olive oil, there really isn't a great deal of science or mystery behind it as many people make it to be. However, there are certain dishes you can't use the oil with, and it has to be kept to a certain temperature setting. Otherwise, you can use the oil in a number of your favorite dishes, and they should turn out great .