A small percentage (2-8%) of our customers eat only Queal. All essential nutrients are available in Queal and theoretically you should be able to live on only Queal. Of course, every body is different. If for instance you do a lot of sports, you may need more sodium/salt and more calories in general.
For most customers, Queal is a perfect breakfast and/or lunch. But I also have some days where I have a meeting in the evening and also eat Queal for dinner as it's just really convenient to do so.
So long story short, yes, but not many people choose to do so.