A newly approved drug for Type 2 diabetes may be a game-changer for treating obesity, too.

Given as a shot once a week, tirzepatide works on two naturally occurring hormones that help tell the brain that you are full. It may be as effective as weight-loss surgery.

"About nine of 10 people in the study lost weight, and the average weight loss for the highest dose was 22.5%, which is something we have never seen before," said study co-author Dr. Ania Jastreboff. She is an associate professor at Yale University School of Medicine and co-director of the Yale Center for Weight Management, in New Haven, Conn.

"These results are an important step forward in potentially expanding effective therapeutic options for people with obesity," Jastreboff said.

Losing weight may boost fertility for obese men