How much weight can you lose from Slim Fast?

I lost 8.5 lbs in 2 weeks by replacing one meal a day with slimfast and have started it up again (I've had another baby and am starting all over again lol) It's a greay way to kick start your weight loss. I have 30 pounds to lose and can hopefully move about 10 kind of quickly. I'm also working out daily and I'm watching my calories but not too much since I'm breastfeeding and I know I need 1500-1800 caloroies a day minimum.