Baby formula is very different than human breast milk, to start with.

Very different.

The biggest difference between breast milk and substitutes is the antibodies.

Baby formula is made to be digestible by babies while Ensure isn’t.

Read some in for from your local health service or lactation consultants… Don’t believe info from formula manufacturers.

At a local hospital there was a nutrion sign, about chest heght, of what nutrients were in each. Formula had a list of may 10-20 things in a few inches of space. The Breastmilk had a list of beneficial nutrients and antibodies that reached the floor.

Other comments seem to be confusing ensure for baby formula. The remainder of those comments are as misinformed, disregard them.

Ensure is a nutrition supplement or replacement for adults. It is a pharmaceutical product intended for use by people who have difficulty taking in enough food. Examples would be cancer patients and those with feeding tubes.

Breast milk is a substance produced by humans for infants and young children. It is composed to provide all needs for a baby and then to supplement during weaning. Notably, it will be much higher in fat. It also contains only those proteins which are digestible to an immature human gut.

Do you have an underlying question?

If you are considering replacing one with the other, no, it is not advisable. It will lead to complications possibly death, sooner or later.

Why is the title of your post a different question than the body of your post?