The gas comment and upsetting of irregularity might seem humorous to the author, but as a biologist and the child of two physicians (one being a gastroenterologist), this seems very disconcerting. Certain foods that contain disproportionate amounts of certain ingredients (e.g. spices, excessive starches, excessive dietary fiber) do upset bowel movement patterns, but a mix of vitamins and nutrients shouldn't do that. It would be interesting to analyze the effects of a protein shake on bowel regularity and the effects of Soylent on bowel regularity on a single subject, and then compare the two.

Also, foul-smelling gas is usually caused when the balance of the gut microbiome is disturbed in some significant way, and this factor combined with the effects described by the author make me very anxious about the probable proliferation of Soylent. It's one thing for short-term effects, but what about Soylent in the long term? A hampered gut microbiome is severely detrimental to the health of a person's immune system.

EDIT: Just saw the amount of sucralose in each serving. Makes the gut irregularity a lot clearer. Still concerning, though.