I noticed after this last patch that my sims hunger goes down crazy fast, too. And then they cook and won't eat. It's annoying.
My boy sims always age up to be super skinny no matter what the parents look like. My girls are always balloons. It's rare that I get a normal size anything so I have to use CAS to fix them. I know how they're supposed to look and I don't play with all perfectly skinny sims. I have a wide variety. But all the kids age up exactly the same. Girl toddler are extreme fat, boy toddlers are extreme skinny and they follow that same path all through life.