It seems to me that the an ideal weight for any given person is relevant to that particular person given his/her height, metabolism, genetic makeup, overall health, etc. My weight has changed a number of times over the years due to many factors. I'm now over 70 and I remember fondly being slim for most of my earlier years. Until I reached my mid-50's, I weighed 115 - 120 lbs. at 5 ft., 5 inches in height. I did lots of walking and loved to hike whenever possible. Suddenly, at age 56, I began to gain weight pretty fast, also lost nearly 2 inches in height, started to lose some body hair, plus I had to struggle to do the walking that once was so easy to do. Long story short, I was ultimately diagnosed with panhypopituitarism - a rare disease caused when the pituitary gland ceases functioning. Since this gland controls the workings of all the other glands in the endocrine system, lots of stuff stops working, including one's metabolism. I take manufactured replacement hormones but will never have a body that functions in a normal way. My endocrinologist has always encouraged me to continue my walking, etc. but has made it clear that I won't ever look like I did prior to getting the disease. Many people have a flawed pituitary gland but it's never diagnosed so they just keep battling their weight issues with much frustration. I'm hoping that someday a treatment will emerge that helps.