This preference is based on their favorite food (see more after the cut). Similar to Growing Together, toddlers will love, like or hate certain foods. So this mod adds two interactions to the high chair to feed toddlers meals or snacks.
I still haven't played that game but I know there's a preference/taste system in the game for baby food, which is really cool! But then I came back to it after TS4 Growing Together came out. This was actually originally part of my Quickie Food and Snacks mod and I abandoned it (this seems to be a theme with me). They literally call the baby food 'sludge' in the game files. If you downloaded both files already, you don't need to redownload anything, just download the file and add to your game.) It's just a little piece of food that toddlers pick up when eating snacks. (Update: I forgot to include one of the files in the Objects file.