I second what SethsMama said.
I walk daily and it definitely helped.
I only gained 7kg during both of my pregnancies, but I lost about 15kg after each within a couple of months. 5kg dropped straight after birth, and a further 10 by 2 hourly BF'ing (and not a lot of sleep

)
I walk about 5km a day (in bursts - we live 10 mins walk from kindy). It keeps the jiggly bits at bay

Edited by MamaPickle