Ok, I'll speak as someone who has actually lost 70 pounds without diet pills, surgery or anything unhealthy. I had to change how I thought about food, eat stuff thats less processed, and find things that I really liked to do for exercise.

I love to bicycle and some days I will be on the trails for 3 hours. I burn 1000 calories per hour while exercising. Also by exercising more and eating better I actually started eating less.