I put on 5 st (yes, not an error!) with my first child. It took me 6 months to lose the weight, by careful eating. It did drop off incredibly quickly as I breast fed - only for 6 weeks - but I'm sure it helped. With my second child 7 yrs later, I put on 4 st and it took me 1 year to lose the weigh, with lots of exercise and stringent dieting. 8 weeks after birth is nothing mackay, it will start to shift when your body has healed from pregnancy, which takes about 3 months according to a friend, who is a personal trainer with expertise in the post pregnant body.