Kitchen is the highest room in the house for power usage.
When I was wiring houses I always ran at least 2 circuits through the kitchen, 3 if it worked out that way.
Most things that you turn on in a kitchen pull at least 10 amps. Jugs, frypans, toasters etc.
Add another high power draw and click goes the breaker.
There also used to be maximum number of power points per circuit.
Now they just specify 2 power circuits I believe, and then any number of outlets. (will have to check the regs again one day. I rarely do domestic)
Those with new homes then have lots of problems, particularly if 2 storey, getting their power to work reasonably well.
They are now pretty much limited to 16 amp breakers, where we could use 20 amp breakers previously.
Cheers
Rob