Not as effective as a bear bag. And it's not just food you have to worry about: soap, toothpaste, flavored drinks. It doesn't matter how "bear proof" a container is, they might come a sniffing. Using a bear bag a good distance away from camp will make them less likely to poke around your tent. For those unaware, a bear bag is a bag that you toss all your smell-ables into at night and suspend from a tree branch high off the ground. Not only does it keep your food safe from being eaten, but being far away from camp means it draws the bears away from where you sleep, which is good for your health.