It really depends on what you want to achieve and how you think to be honest.

I know a lot of competitive cyclists who all eat after their morning session.

Some people believe if you eat after you burn that food better and quicker.

If you get tired during your walk or take a long time to recover, then I'd suggest something light before your walk.

Me personally, I never eat before I train. Training with food in my stomach just makes me feel like a concrete slab, everything feels harder, and I usually feel sick. So those sessions are never good ones!

If the girls are hungry you could always give them some toast to munch whilst you walk.