I have noticed an increased sense of lethargy and awareness of my bones and teeth. As the day goes on, I have a visceral craving for caloric intake other than Soylent. I have solved this partially by adding bananas, nectarines, etc. into the water & Soylent blend to create a smoothie. But at some point I am really craving a boost of the meat protein variety. Tonight I may go to a DJ type event (tribal flute in hand, natch) and for the extra energy eat some vegetables.
One interesting aspect of this Soylent diet experiment is that I am reading the Martian at the moment. While the protagonist quickly starts creating soil on the HAB floor to grow potatoes, he seems also subsists on packaged food that may be in fact a future evolution of Soylent. This synchronicity is deepening my appreciation of a very good story and in turn affecting my conception of Cowachunga - the framework evolved in surprising ways today, through talking with Nils.
* Full disclosure, I cheated slightly last night and that was with several handfuls of tortilla chips given out for free with my Tecate purchase at a Mexican supermarket down the road.
** As a side note, I was vegetarian for two years in Santa Cruz, California, added Bragg's aminos and stuff to my food. At a certain point my circulation got kind of weak and I switched back to meat.