TC, do you see any relationship between a “chubby” baby and an overweight adult? I don’t. Babies should have nicely rounded bodies and faces, or I would suspect they are not getting proper nutrition.
No, I don't. Most of my children were quite chubby as babies, but none of our various doctors ever considered one "overweight." My mother couldn't assimilate the idea that a baby who was exclusively nursing was very unlikely to have a weight problem, though.
One of the children has a weight problem now, in his teens. I attribute this to his preferring, as his mother does, reading and FReeping (or equivalent) and crafts and puzzles to being outside exercising. Vanity keeps me from being overweight, but this child is so proud of his intelligence that he doesn't seem to mind his avoirdupois. When he puts on his suit for debate tournaments, he looks like a traditional Southern politician, biscuits and gravy every morning at the diner ...
Years ago I remember reading some “study” showing babies or infants that were obese tended toward obesity later in life. The theory was that they developed more fat cells as infants and while you can lose fat there remained an excess number of fat cells thus making losing weight harder...