I know that while pregnant, the digestion slows down, to try to wring more nutrition from what you eat. I also know that I eat about the same as my ex and my husband and both managed to get fat. Also I drop weight when stressed and maintain a normal BMI when not so stressed, but others I know gain when stressed.

It all is very interesting to me, but so strange that it's broken for so many people, and most all in the direction of overweight.