Heres a little story about me Born in the mountains of Montana, I grew very tall very fast. Like over six feet tall by the time I was 12 years old. I dont know how my parents could afford to feed me because I consumed everything in sight. I was able to eat what I wanted in any amount I wanted and never gain a pound all through childhood and early adult life. I even tried to put on weight, because 6'5" and 160 lbs was just too skinny to be sexy. Then at the age of 27 I went to work in the oilfield roughnecking on drilling rigs. I put on 35 lbs of muscle in a very short time (maybe 3 or 4 months). I maintained this new physique for the next 5 years. I then decided to go back into aviation. thats when the weight problem began. No more strenuous labor 8 hours a day. Of course I had to keep eating the same things in the same amounts. the weight continued to climb for the next ten years. I have been up and down since then mostly between 240 and300. I dont know the medical reasons for the changes in my metabolism, but I do know my eating habits and my activity level have to change for me to live the active life I very much desire.