Feed it twice a day, with 20% of the food intake during the day and 80% at night.
Each hamster has a different food intake.
So, it can be divided according to age:
For one - or two - month - old hamsters: 10 - 20 grams a day;
For three - or four - month - old hamsters: 20 - 30 grams a day;
For five - or six - month - old hamsters: 30 - 45 grams a day;
For hamsters over seven months old (fatter hamsters can be fed more, if they weren't overfed before, feed them less): more than 50 grams a day.
It's best not to feed them hot - natured things like sunflower seeds, hemp seeds, and mealworms.
Many hamsters have red and swollen eyes or even go blind because of this. A friend of mine fed his hamster too many hemp seeds, which led to the hamster's blindness and finally its death. (These things are also nutritious. It doesn't mean they can't be fed at all, but they should be fed in small quantities. About one piece (of hemp seed, sunflower seed, or mealworm, choose one) every one or two days.)