I read a sci-fi novel years ago that was set in the not-too-distant future and featured a protagonist who was fond of "purple-flavored" breakfast cereal.

Gisting a short sci-fi story (or a very long pun), also focusing on food:
On a far-future human-inhabited planet, the culinary art is deemed by far the highest art form, the acme of which is an annual planet-wide competition. Past winners are revered, and their creations immortalized, like the heroes of sport or myth. Since all food is synthetic, this competition is chemical as much as culinary, as the chef's struggle each year to develop new and proprietary flavorings.

The protagonist emerges as the stunningly unexpected victor in the annual contest, his dish wholley novel, his flavoring completely unique, representing a breakthrough such as occurs but once a century.

But "all heck breaks loose" when it is discovered that his new secret ingredient is garlic -- that is, a substance which to everyone's utter disgust and revulsion actual grows in dirt. What a revolting, literally nauseating thought: to have actually put something like that in one's mouth!

The protagonist is exiled from the planet in disgrace. For as the final sentence of the story states, his actions were simply not in good taste.