"Ensure Complete, one simple choice for 4-in-1 nutrition. Each delicious shake provides balanced nutrition and targeted muscle, heart, immune, and bone health benefits. It’s a simple choice to get the right nutrients in the right amounts to help you stay strong. Take charge of your health and your nutrition with Ensure Complete!"
From their FAQ: http://ensure.ca/en/faq/
"For how long can I use Ensure? Ensure products deliver complete and balanced nutrition that is always beneficial. There is no time limit to using Ensure products. In fact, long-term use is encouraged if you’re at a nutritional risk (for example, if you’re an older adult)."
"Can Ensure replace a meal? Yes. Ensure products are complete and balanced, when used in appropriate amounts they can be used to replace meals."
For instance, that 260% protein you cited is about half the protein I take in a day.
Also, FYI, the danger in taking in too much protein is very much overblown. I doubt you could actually consume enough protein to make it a problem unless you had a medical problem with your kidneys already.
In the FAQ I pointed to they say that Ensure is safe for long term use, is complete, and they answer a question about how many servings a day are necessary for meet your needs.
[1]actually abbot and the like will advertise as being a full meal replacement... for situations where people have medical need and are being monitored by a medical staff, which is to say, in situations where problems might be caught and addressed.
[2]Don't want to eat three multi dish meals a day at 8,12,7? Human bodies have plenty of reserves to deal with out getting 100% of their RDI every single day, just so long as it averages out over a week or two.
But you still want something to keep the stomach from rumbling? Great, the supermarket is chock-a-block full of foods that need no preperation and supply a wide variety of nutrients, either in the form of specialized products (Ensure, Clif bars, various other supplements/diet products) or just no-prep food: pouch of tuna, quart of milk, yogurt, that thing of trail mix that's clearly just muesli with extra peanuts, sack of pre hard-boiled eggs. Whatever.