As product placements.
Cigarettes:L&M was smoked by Paul Newman, Lucky Strike by Johnny Depp, Marlboro by...
Bogart had favourite bourbon, and so did Connery his scotch.
In war propaganda movies in USA, under Edgar Hoover's command, the milk was drunk during the meals.
It is interesting to follow highs and downs of some products.
In TV series Crime Story from eighties the famous laetrile ("B 17", in fact apricot stones) was mentioned as not approved experimental drug for cancer, when Ray Luca and Pauli Tagliatella characters got sick after they looked for shelter in Nevada during atomic bomb test.
15 years later in a episode of Law&Order, this laetrile was condemned as a quack's medicine which poisoned a woman. As they questioned a number of suspects and witnesses, the detectives have been extensively eaten junk food in form of pizza slices and they drank milk from tetra paks! It was clear (*almost subliminal) message to the audience not to stick with macrobiotics but to Rumsfeld's aspartam and junk food in general.
In western movies and TV series, people eat T bone steaks, roast potatoes and drink bourbon and coffee, never water.
In French movies and tv series people drink only hot cocoa and eat toasted rolls with butter and jam.
In British movies and tv series people eat been and sausages and fried eggs for breakfast.