Something that pisses me off more than anything is when large, irresponsible brands take a health trend, or a truly healthy food and reproduce it in a dishonest, cheap manner. Enter: olive oil.
Olive oil is by no means a new health trend. The Mediterranean diet (and thus, olive consumption) has long been touted for its heart health benefits and slimming effects. Regardless of your style of eating, it's likely that you are buying and eating olive oil. There is also a high chance that the olive oil you're buying is hardly olive oil at all, but rather a mix of some olive and a lot of cheap vegetable oil and dye (it's estimated that 70% of olive oil sold in the U.S. is not pure). WTF is wrong with the world?!
So, how do you know if your olive oil is 100% olive oil?
Check for harvest date. Not "packed date." HARVEST date. This is by far the best test. In order for a company to include a harvest date, the contents must all come from the same batch of olives, and nothing else. I now challenge you to go to a standard grocery store and you will maybe find one or two bottles with a harvest date out of dozens.
Choose dark bottles. Responsible olive oil producers know that olive oil is fragile, and requires protection from light and heat. Once you're home store your olive oil in a cool, dark place. If you buy olive oil in large batches, store most of it in a cool, dark place and keep a small amount in a dark bottle for easy access.
Buy locally. Get to know your local farmers and buy from them! This is my rule for almost everything, but I know it's not always possible. California Olive Ranch (on the right side of my second picture above) is a brand that sells in most grocery stores and is tried and true.