Well, you're definitely right in ways because where I firmly believe in feeding a baby when he's hungry, and stopping when he's done, I also have witnessed firsthand an overweight, overfed baby. It was very sad. He was so big, I think he weighed over 30lbs at like 8 months or something. And he wasn't long or big boned. He was average in that area, but just very overweight. He actually had a lot of trouble breathing because of it. He was very unhealthy. I don't completely recall the exact details, but when his mother told me what he ate in one day I was blown away. It was a ton. It was like (for example) 5-6 8oz bottles a day with cereal in them, and 3 tall jars of baby food. In one day!!! Or something similar, you catch my drift.
I am also a strong believer of cereal NOT belonging in bottles. A lot of people do it to resolve spit up or to try and get their babies to sleep through the night longer. But that is a huge contributer to babies gaining too much weight. Either they can eat it off of a spoon, or they can't. I'm not saying its harmful (a lot of people do it) but it is risky as far as the weight thing.
But that baby is 3 yrs old now, and he is kind of a big boy, but not so much overweight anymore. Still big, still chunky, but not unhealthy or huge or anything. And my son was a total chunker as a baby (not overweight, but quite chubby) and started slimming out after he turned one and now he's 2 and he's perfectly average sized, almost turning slim these days. So that also tells us that even if our babies get chunky, they tend to slim out to where they're supposed to be all on their own as they get older.