There may come a time when you'll be worried about your weight, but at 4 months you can only be proud of your baby fat. Your cheeks are fat, your belly is fat, even your feet are fat. It is so cute I can hardly take it. Your cute fatness is especially well displayed at bath time, when I can't help but squeal at the sight of your chubbiness.
Which confuses you considerably, Johnny, and it makes you even cuter.