While coffee has enormous health benefits (reducing diabetes, Parkinson’s, heart disease, and cancer), there’s some controversy over how it affects creativity. Some scientists believe coffee reduces creativity, according to an article by Maria Konnikova in The New Yorker:
“Creative insights and imaginative solutions often occur when we stop working on a particular problem and let our mind move on to something unrelated [but] caffeine prevents our focus from becoming too diffuse; it instead hones our attention in a hyper-vigilant fashion.”
In other words, caffeine keeps your mind from wandering, which is part of the creative process. The problem with this theory is that it may overestimate the importance of free association (i.e. mind wandering) in the creative process.