Last week, Kate Middleton briefly bared her tummy while playing volleyball in her first solo public appearance since giving birth two months ago, and her stomach was completely flat!

Even Kim Kardashian is already taking selfies, and North West is only four months old. Naturally, these celebrities have means and ways to achieve their ideal post-baby weight loss. But what about the rest of us? How long does it really take to get back to your pre-baby body?

Mitzi Dulan, R.D., author of The Pinterest Diet, says that for most women it takes anywhere between three months to a year to shed the excess pounds. But for some moms, it can take longer. But there's one important thing to keep in mind: The more weight you gain while pregnant, the longer it'll take for you to get back to your pre-baby size. The trick is to not take the whole "eating for two" thing literally - because your body actually doesn't need that many extra calories.

Dulan's advice for struggling new moms who want to drop those pounds is:

1. Don't drink your calories - stick to water or zero-calorie flavored sparkling waters.
2. Have protein at every meal to keep hunger in check.
3. Don't eat after dinner (this is when many people consume excess calories).
4. Load up on juicy foods that contain lots of filling water.
5. Stay active - get in as much exercise, or do things that will make you get up and move about.

Try these tips out and see if they work for you!

Image: Reuters