Soft drink
Soft drinks (also, pop, soda, juice and about a thousand other names) is fizzy stuff that comes in cans. It is available in both sugared and diet versions. It is not an adequate fuel source for Transformers.
Optimus Prime (more than once) and his near-identical twin have been known to shill for certain manufacturers.
Fiction
Marvel Comics continuity
Shady auto dealer Big Steve immobilized the Throttlebots by filling their tanks with sugary soda, allowing RAAT to capture them. Used Autobots
Generation 1 cartoon continuity
The Transformers cartoon
Powerglide shoots a vending machine and blows a huge hole in it. This somehow causes a firehose-like torrent of soda to come shooting out of the machine. The Girl Who Loved Powerglide
Victory cartoon
Jean Minakaze nearly choked on his soft drink when the Rescue Patrol Team informed him that Holi was being so serious because he was worried about his girlfriend, Clipper, down on Micro. Planet Micro - The Mysterious Warrior
Cybertron cartoon
Jolt watched a home movie of the young Coby Hansen enjoying a glass of a soft drink he called "green gloop" with a scoop of ice cream. Collapse.
Live-action film series
Transformers (2007) film
Pepsi ads and Mountain Dew vending machines can be seen in Mission City.
IDW Revenge of the Fallen prequel comics
Dispensor hit Sam Witwicky on the head with a soft drink can, leading Ratchet to sternly lecture on the dangers of soft drinks.
IDW Generation 1 continuity
Roller drank Kremzeek!-brand soft drink, laced with circuit speeders to give him an "edge", despite Rung's objection that it could cause instant spark failure. Elegant Chaos Part 1: All Our Parlous Yesterdays
