Yep, it is normal for them to do that. It's abnormal for babies to sleep through from a young age and never wake, quite frankly

There's a great article on waking and needing helpt o sleep in the latest Essence mag.
@ 3months, 80% of babies wake adn need helpt o get back to sleep
@ 6 months, 75% wake
@ 12 months 50% still wake
And about a third of children still wake and need a parents help to get back to sleep until they are 4

so it's no fun, but it's certainly normal

I certainly know DS's waking etc had nothing whatsoever to do with nutrition or diet, as changes (even night weaning) made no difference.

After all that Chartlotte, I don't blame you wanting to hold off a bit!