Hamsters have cheeck pouches in which they will collect food that they will store somewhere in their cage. So an empty food dish does not necessarily mean your hamster was hungry. It just stowed its food away, safely hidden from your prying eyes.

You can use any generic hamster mix that is sold in pet shops for your Roborovski, but I prefer the "premium" foods. Those are higher in protein (min. 16%) and other nutriants. You will be rewarded by a happier and healthier pet and the mixes only cost a little bit extra.

Another good tip is: Buy a type of food that is specifically intended for (dwarf)hamsters. All rodents and other mammals are different in their feeding habits and needs. Giving a hamster a type of mix that is intended for instance for a guinea-pig or a rabbit will mean that it might not receive all the nutrients a hamster needs to stay healthy. Hamster mixes labeled "dwarf hamster" may also contain smaller 'bite size' bits, that are easier to chew on for dwarf hamsters.

Witte Molen Dwarf Hamster (currently using)

Still the reigning champion for me. The protein levels are just right (17%) And it contains dried meal worms. By far the food my dwarf hamsters like best. The dishes are cleaned out every time.

Hope Farms Hamster Super (currently using)

Very good and complete hamster food. It can by kind of boring, because it is composed of uniform pellets, which contains all of the nutrients. The pellets are high in protein and hamsters seem to like them. The smell reminds me of porridge and it probably tastes somewhat similair too. These pellets are not te be confused with the pellets intended for rabbits, which contain only grasses and hay. (Hamsters don't like those.)
I give these pellets along side their main mix (WM Country) It keepst them nice and round.

You can vary your hamsters diet by giving it some bread or fruit or vegetables. You have to be careful with the amount of wet foods, like fruit and vegetables, because they can get diarrhoea if they eat too much of it. They also like an occassional nip of cooked chicken, yoghurt or a dog biscuit. Don't give them cheese, as it contains to much salt and NO chocolate, which is poisonous for almost any animal!

Although not sounding too nice you can give them certain insects too, like small crickets and mealworms. You can buy them in a petshop. Please do not give your hamster insects if you are not sure which ones are suitable for them or insects from outside (they may contain pesticides).

A long and good list of what you can and cannot give your hamster to eat, can be found at: The Petwebsite

Beaphar XtraVital

Good hamster mix. I used to buy this partly because of the Roborovovski on the front of the package, but it turned out to be quite a good hamster mix also. It was generally eaten well by my Roborovski.

Harry Hamster

The ingredients are well balanced and it is generally a fine hamster mix. My Roborovskis did not like it, so I have not used it for very long