I agree with what P_anda has posted and will give my own thinking behind human cereals. I used to be a fan of this but have changed my views greatly. The reason being, most of these (not all) are processed. In other words, mucked around with! Unless you go for plain organic porridge oats (Tesco do a lovely jumbo organic porridge oats), I would be highly wary of adding these to a hamsters food. They will contain hidden salt & sugar, even though the box will say `wholegrain` or `free from additives` or `no added sugar`...that type of thing.
In a nutshell, hamsters eat a very bland diet in the natural setting, so this means small seeds, grains, plant roots and shoots and berries when they can get them. They don`t have access to weetabix or puffed rice.
Feed your hamsters on the best commercial hamster food mix you feel is best (I like Burgess Supahamster Harvest - natural) for all dwarf hamsters and add natural seeds and grains to this to add more variety. Things you might naturally associate a hamster to come actoss in the wild like millet seed, hemp seed, buckwheat, oats and insects like mealworms and crickets..
Most dwarf hamsters come from Mongolia, Russia, and the borders of China. So because they cover a vast area of plains, they won`t all have the same diets, but they will forage for what they can find and store this away, just as our little ones do in captivity. This is when we disturb the nest and wonder why the hamster has peed on it`s food? This because it thinks you are a predator who has come to pinch it`s stash!
And it may also move it`s nest due to the same disturbance, which is why the nest and food store is highly important to your hamster. It`s mimmicking what it would do in the wild.
But going back to the original subject, I believe it`s best not to venture into these human foods and stick to what a hamster thrives on. Seeds, grains and dead insects with the little pieces of fresh raw veg a few time a week for their vitamin content.
Many hamsters` health suffer because they are fed additional foodstuffs that are not only bad for them, but reduce their lifespan because their bodies cannot deal with them the same way we can.
My advice would be, forget cereals and human foods.