Herbalife? Advocare? While pregnant

Has anyone asked their doctor about taking meal replacement shakes? Like Herbalife and advocare? 
I plan to ask at my next appointment but that's in 2 weeks. I've been craving my Herbalife shakes! 
I'm ALWAYS hungry and at 14 weeks already gained 4 lbs so I'm curious as this may be a good snack option as well to curb my appetite.