The answer to this question is yes and no. Most people get confused with the term Brazilian butt lift. The Brazilian butt lift is actually a fat transfer procedure. Fat will be removed from your waist, thighs, lower and upper back, abdomen etc. This is all performed with liposuction. By removing fat from these areas, your waist to hip proportions are improved significantly. Now, all the fat that is removed is injected into the buttock thus creating a beautiful shape.
Now, you need to understand how the fat behaves. When fat is removed and transplanted to the buttock, it takes a few weeks to have its own blood supply. Once everything settles, the fat will behave the same way as the area where it was harvested. In other words, if you lose weight, your butt will get smaller like any part of your body. Now, your proportions will still be the same. This means that your waist to hip ratio will be the same and your butt will still look prominent. This procedure will not only create a nice behind but will improve your proportions.