I think there is some merit to the concept of set points. For women, from what I have read, our set points are determined during puberty, pregnancy and menopause.
I was morbidly obese as a child. But around puberty, I did thin out to a mere over weight lol. When I reach my adult height, I seemed to at about 165ish pound. And from my later teens until pregnancy, if I stopped dieting (but did not binge, that's different) worked out moderately, I'd settle right around 160-165, pretty much effortlessly. Now when I got pregnant the first time, I just went crazy eating whatever...And I gained to about 240 (see siggy)...after pregnancy, I did have to try to lose, but getting to my previous set point was not too too hard. With my other two pregnancies I was more careful about what I ate, and I exercised the last 2 trimesters with my last, but the weight just got within the 200 something range.
The crazy part is, the way I ate when pregnant, I can mirror that when not preg and I will get to maybe 170ish...No matter how much a binged and sat around I never got over 200 not pregnant! So I think there is something true about set points.
I do believe that to maintain a lower weight 145 or 130 I will have to be more mindful of my exercise (run a higher weekly mileage) and a bit more careful with what I eat. But I do think its doable.
I could be totally wrong here. This is just the theory I subscribe to. lol