That’s quite bad though, because Soylent is supposed to be “for everybody” or at least most people, and most people in the United States (where I believe Soylent is most agressively marketed) are overweight or obese. The overweight rate (includes obesity) was 69% in 2010 in the United States according to the CDC (I think it is about the same today). Disclaimer: I’m American. Soylent might be more successful if it was a weight loss product. I think Rosa should develop a weight loss product if possible.
Though participants gained weight during monitoring, this is typical for weight loss studies. You should consider whether it was better than the high carb diets. Low carb diets show this effect too. But the total weight lost (notwithstanding weight gained during monitoring) is usually greater the lower the diet is in carbs.
This youtube video summarizes a 2006 study of diets, low vs high carb. They found all groups had trouble sticking to their diets: the high carb group was assigned 90% carb but couldn’t achieve it; the low carb group was assigned 10% carb but couldn’t achieve it. Even so, the lowest carb group (Atkins) lost the most weight. Also their blood markers improved the most. Most troubling is that on average, the study participants in the Atkins group (which lost the most weight), didn’t lose enough weight to make a significant difference in their overall health. We need a diet even better than Atkins and I don’t think one exists. Soylent could help here by making diet adherence easier.