Great idea! The problem is this would create a culture of heavy breathers hogging the food and light breathers attempting to reduce their impact on the environment. Over time humans would segment in to two species: one large, heavy, and strong, the other light, intelligent, and agile.
The debate over how to breathe would eventually lead to violent conflict and the soylent-air factories would become strategic resources. Eventually an ultimate weapon would be developed by the brutish segment, who would not fully understand the implications of their discovery. The Final Solution is meant to cause a chain reaction to destroy the soylent-air factories held by the opposition, but the flawed mathematical models of the brutes could not predict the drastic implications of their aggression.
On judgement day the weapon is fired for the first time and the chain reaction leaps from the factory to the greater atmosphere, combusting all airborne sugars, proteins, and lipids across the entire globe, releasing stored electrochemical energy on an astrophysical scale.
The earth and life as we know it comes to a fiery end all because of the hubris of a humble company near the turn of the 21st century: Rosa Labs.
I think the drink is easy enough. For now...