Meal-replacment drinks are dubious at best.
At the end of the day, a well-balanced diet and regular exercise
work best.
I remember back when I was in the army, one of the medics under me
was determined to lose weight.... and to that end, he bought
high-fiber pills. He gloated to me that 'Each pill contains the
same amount of fiber as one tablespoon of green vegetables.'
At which I retorted: 'Why don't you just eat one extra tablespoon
of veggies then?' 
