Natural Weight Loss

I have been overweight for a long time. When I was pregnant with my son, I was 195 lbs. Now at age 31, I am 390 lbs and I'm only 5'3". I've considered gastric bypass but that's way too drastic for me (85% of the stomach being cut away, no thank you). I've considered the Lap ban but I heard that too can come with complications. I want to lose the weight the natural way, not by surgery. It's hard for me to go up and down stairs because my knees hurt. At one point, I had severe hip and back pain and I'm prediabetic (most of my adult family members on my father's side are diabetic). Any suggestions will be greatly appreciated