To me the problem is the combination. Soylent market themselves as a full meal replacement solution, no extra nutrtition required. This means they need to prove

To me the problem is the combination. Soylent market themselves as a full meal replacement solution, no extra nutrtition required. This means they need to prove that a) it does provide everything the body needs, and b) that continuous consumption has no bad side effects. Mcdonalds on the other hand never market their food as a complete meal replacement solution. In fact, here in the uk, they're very careful to point out you still need a healthy balanced diet (admittedly due to regulations, but still... They do it, Soylent don't)