Approved 20 years ago as a treatment for diabetes, GLP-1 drugs have been found also to help patients significantly reduce weight. More than 30 million people in the U.S. have had their lives changed by GLP-1 medications. But there have also been troubling side effects reported. Correspondent Tracy Smith talks with experts who say the drugs might prove useful in treating other diseases associated with obesity (including cancer); and with patients who have taken GLP-1 drugs and experienced widely varying reactions.