Originally posted on futurefood.hellobox.co.
Top link is to abstract; click Details for link to full paper and comments. A group of undergraduate researchers at UC Berkeley have studied the effect of a switch to 100% Soylent on the population of bacteria in the gut (PDF of full paper).
This is a very relevant issue to study, first because people often find that their digestive tracts behave differently (farts, diarrhea) on switching to a meal replacement, and second because of lingering questions on the long-term health effects of meal replacements.
The study group of nine subjects ate “a regular diet for 2 days, a Soylent-only diet (five servings of Soylent daily and water as needed) for 4 days, and a regular diet for 4 days.” Four control subjects kept to their normal diets for the same period.
Subjects all collected stool samples which were submitted to the commercial DNA sampling program uBiome (“the world’s first sequencing-based clinical microbiome screening test, providing detailed and accurate information to help you understand your gut health”), resulting in uniform reporting of any changes in the composition of their gut flora. (The full paper describes the technology in detail.)
For each individual, the relative abundances of four dominant phyla (Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria) were normalized by subtracting the baseline community as established in phase A.
So what was the short-term effect of an all-Soylent diet?