Years ago, a canned soup company got in trouble because its advertising implied there were more vegetables in its vegetable soup than there really were. Specifically, the photo in its ad was considered deceptive. Turns out, the canned soup folks had put clear marbles into the bowl before filling it with soup; the vegetables sat on top of the marbles, peaking out of the liquid, giving the impression of soup brimming with vegetables.
Most food styling tricks are not meant to deceive but to simply make food appear appetizing. Most consumers know this and are okay with cake mix ads showing perfectly frosted cakes with nary a stray crumb -- like these gorgeous examples from Betty Crocker.
Food stylists are professionals whose job it is to make food look gorgeous despite hot studio lighting and photo shoots that often last all day. And their bag of tricks is fascinating.
For example, they use white glue instead of milk when photographing bowls of cereal. For one thing, the glue won't curdle. For another, it won't soak into the cereal. And it's easier to control -- no small thing to a food stylist who's spent Lord knows how much time sifting through boxes of corn flakes and picking out the most attractive flakes.