Ask, when you buy, what the hamster has been fed on as, although hamsters like a variety of foods, introducing too many new foods at one time can cause tummy upsets. ALWAYS introduce greens and any new foods gradually and in very small amounts if you are not sure what your hamster has been fed before.
The basic and major part of the diet should be a proprietary dry hamster mix which can be bought from a pet shop. This will be a mixture of seeds, crushed oats, flaked maize, sunflower seeds, locust beans, peanuts etc. with some hard dry biscuit. All these are "hard" and good for the hamster's teeth, and a small handful of this mixture should be given each day. As a treat, more hard dry biscuits can be given, such as "all in one" dry cat rings or a small Bonio, again good for the teeth.
Hamsters are hoarders - they store their food behind or under their
beds so greens and soft foods must only be given in moderation, otherwise
any uneaten will spoil. As hamsters put their food into their cheek
pouches "sticky" and "sharp" foods should be avoided. Chocolate (which can
melt when pouched) and cornflakes (which can scratch the pouches) are two
such foods.Greens
Carrots, cabbage, cauliflower, broccoli, sprouts, broad beans, peas, runner beans, apple, bean sprouts, sweet corn, cooked potato and cucumber can all be given in small quantities. A slice of apple OR the core, OR a small floret of cauliflower, OR a small sprout, OR two broad beans would be enough at any one time. You will soon discover what your hamster enjoys and how much your hamster can eat without any tummy upset. A very special treat would be a raisin or sultana. These are greatly enjoyed, as is lettuce but too much lettuce is not good for the hamster.
Wild Greens
Hamsters really enjoy dandelions and groundsel but you have to be especially careful about these - picked by the roadside they could have been sprayed or covered with car fumes etc. so unless you can be certain that they are really SAFE to eat don't give them to your hamster. All greens should be fresh and washed.
To help your hamster grow strong bones and teeth some milky foods can be given. Some will enjoy milk on its own, others a little runny porridge, a few rice krispies with milk or even bread and milk, all without sugar of course. Any of these should be removed before the milk sours, if uneaten. Fresh water, preferably in a bottle, should ALWAYS be available.
All species of hamster may be fed as above, but dwarf hamsters (Russian, Chinese etc) will appreciate the smaller type of seed - millet, budgie seed, foreign finch seed - in addition.