I have a doubt.
Part of the gastric system relies on information from your mouth, like chewing and suchlike to prepare the body for what's to come.
The senses in your mouth tell the brain what is going on and the brain in turn tells the stomach, pancreas and associated bits to get a move on.
As I'm sure people who have eaten chewing gum can testify, mimicking eating food doesn't half play havoc with your gut and so, conversely, not giving your gastric system an heads up must have some consequences.
I always considered the "everything you need in one handy serving" would have been like a flapjack, indeed, for about three years I made flapjacks every week, to eat at work. Easy to make, plenty of options for flavouring and if enough consideration has gone into it, a perfect nutritional meal, that provides energy throughout the day.