Here is my take. As a child I was a complete and utter pig. I ate like crazy for the sheer love of it. At 13 years of age I weighed close to 250# and had a waist line so that no children's clothing would fit me! Finally, I got my act together at age fourteen. I started with what many would call a starvation diet. Breakfast was an apple or something. Lunch, carrots or something, and dinner was normal. Over 3 months, I lost 50 (!!!) pounds.

Of course, being at the weight I was at was still considered unhealthy, but I remained steady at approximately 200#. Four months later, I decided to go even lower. I did every kind of simple excercise I could think of, from crunches, to push-ups, pull-ups, the works. It was a long, Long, LONG 4 months, but I managed to bring myself down to about 170. I remained at that weight for three years.

Then, one summer, I decided to really push the envelope. I did runs (something that is just not easy for me, I have never been good at high-aerobic exercise), walks, swimming, and quite a bit of "starvation dieting" and managed to get myself down to 140. Now, given that I am barely 5'10", this was below my ideal weight level, but I managed to push it even further to one point where I was at 130. I was getting near 100% of my vitamins, minerals and such, but for some reason, I just kept losing. Then I stopped exercising, and just maintained a healthy diet. I am now in "ideal" 150-160# range (I haven't checked in a long while), I can do mild aerobic exercise, I can bike 50k a day, and I can eat a fair amount without gaining any (significant) weight.

So, what happened?

I have no scientific background, but I'd have to say I eased my body into it. It definitely went into starvation mode, but when I ballooned back from the 130-140, it seemed to be quite content at the 150-160 level and had no desire to return to my previous weight.

However, I can't say genetics had much to do with it. Both sides of my family aren't known for having "healthy" bodies, and all are overweight to a fair extent. So I have a hard time swallowing the "its genetics pill". Saying that removes a lot (not all) of the responsibility and allows the obese individual to simply give up and say "c'est la vie!".

And to those who might be curious, I doubt I am some fluke. My mom asked me to help her lose weight, and I followed a similar (though less extreme) regime with her, and her body lost a solid 20# and she has kept it off, not through anything excessive, but simply not by over eating.

From my point of view, it is a choice. Fat people can become thin, thin people fat.