28/06/2010 10:51 BST | Updated 22/05/2015 10:12 BST

Extreme Post-Pregnancy Weight Loss: Is It Safe?

For a few years now, celebrities have become well known for pinging back into shape fairly quickly after pregnancy. Now an assortment of celebrities have been seen out in tiny six or eight jeans just months or even weeks after giving birth.

Sarah Michelle Geller (right) gave birth to baby Charlotte Grace Prince last September, and has recently been seen looking a lot slimmer than pre-pregnancy. Charlotte Church seems to have also undertaken a fairly radical diet to drop down to a size 8 after the birth of her second child.

This weigh loss 'race' influences normal parents too, who don't have the benefits of personal trainers, nannies and dietitians.

The NHS encourages mothers to undertake a healthy diet after childbirth, particularly when undertaking breastfeeding. Breastfeeding takes up a lot of energy, so whilst you may naturally lose some weight from this, you'll also need to eat a regular, balanced diet in order to provide the baby with the best nutrients.

The BabyCentre recommends that any dieting is left until after the first six-week postpartum checkup, or until your baby is two months if you're breastfeeding.

What do you think about celeb mums who lose weight quickly? Here are a few more mums who lost the baby weight quickly.

Angelina Jolie, pictured just a couple of months after giving birth to twins Knox and Vivienne.

Mrs Beckham has a tiny figure for a mother of three, although she admits to being careful with her diet and working out.

Katie Price, also a mum-of-three, shows off her size 6 figure.