Some cheap bike locks can be easily cut with bolt cutters. If you have an expensive bike you do not want to take the chances with a dinky chain lock.
With only a few pounds of beef jerky you can make a reliable, stylish bike lock. Some premium types of beef jerky cannot be chewed or cut though.
I have an expensive mountain bike that I wouldn't trust with any lock other than my jerky lock. I used Sweet & Spicy flavor to make my lock and get compliments on it everywhere I go. For the past two years I have been using this lock and my bike has never been stolen.
I took my bike on a weekend trip to Tijuana and even there it did not get stolen. I did, however, catch a local man trying to chew through the lock. What I gathered from his broken spanglish was that he wasn't trying to steal the bike but he was just hungry and Sweet & Spicy was his favorite flavor! We chatted for a while about our common interest in the healthy snack and then drank some tequila and went to a local strip club together. I will forever remember my Mexican friend for life, Aleja.