Seed mixes can usually be bought in two forms, those that include a protein source and those that do not. If you prefer to feed your own protein source, then make sure the seed mix is one that does not already contain protein.
Hamsters are omnivores, meaning they need both plants and meat in their diet. In the wild, they get protein from eating insects. To replicate their natural diet as much as possible, it is advised to feed live insects to your hamster. Not only does this give them the protein they require, but the insects can also be “gut loaded” with vegetables in order to increase their nutritional value.
Suitable insects to feed your hamster include:  meal worms, black soldier fly larvae, crickets, silkworms, wax worms, and small morio worms or locusts. It’s a great idea to add them to your hamsters sandpit or digging box, so it replicates how hamsters find insects in the wild, (or you can of course use tweezers to feed insects directly to your hamster if you’re squeamish!). Insects can also be provided in freeze-dried form. While they still give your hamster the protein they need, they are not quite as nutritional as live insects. Some hamsters refuse to eat dried insects, so in these cases it is advised to feed live insects instead.
Other protein sources include plain cooked chicken or turkey (either fresh or freeze-dried) and plain cooked egg.