My dad used to 'drink' something similar for quite some time (through an intrastomal device actually - as he'd had a stroke and couldn't really swallow properly). It was suggested/recommended by the hospital. It's very nutritious - has just about everything your body needs (including some fibre - but a fibre supplement is helpful as well). You could read the ingredients on the back of a can and see what % of daily recommended amounts of everything are really in it. However, I might add that if you're drinking it to lose weight, it would still be best to have an otherwise balanced diet, and not use it for all 3 meals. Not to mention that if it IS to lose weight - eventually going back to "real" food (which you will) is going to make it hard to keep it off - as is with all "diets" that are not a lifestyle change...
Why not Google the product and you'll find out what you wish to know further...